Over 151 Years of Service to the Furniture Industry

 Furniture World Logo

Bedding Anatomy 101

Furniture World Magazine
Volume 142 NO. 3 July/August


The past seven installments in this series on selling better bedding presented tools and techniques that the best retail furniture stores use to price, promote and present mattresses, pillows, mattress protectors and foundations.

For readers who may have missed any of these, please visit http:// www.furninfo.com/series/bedding to see a complete list and links to these articles.

This time, we start an exploration of mattress components and construction.

Mattress Specs

In terms of the sales process, components (mattress specs) can be thought of as features that have associated benefits. Benefits, in turn, provide customers with advantages that are appropriate only when a customer has a need for that specific advantage.

In “Bedding Anatomy 101” our discussion will be framed in terms of how component/ construction information should be introduced into the sales process. In the September/ October issue of Furniture World, we will start to delve deeper into mattress anatomy, organizing and presenting the different kinds of springs, foams, gels, cushioning products and ticking.

Consumer Research

Let’s start with some research. Furniture World spoke with Michael Magnuson, the founder and CEO of GoodBed.com, a leading mattress research destination for consumers, and targeted advertising platform for mattress retailers.

“We asked people what would get them more comfortable with the price of a good mattress,” he said. “Eight percent of people chose detailed product specifications as their number one answer. So, there’s a subset of consumers who feel that specifications are the most important factor in determining the appropriate price to pay for a mattress. In this case, we only allowed people to mark their top choice, so there is also another portion of shoppers that factor product specs into their purchase decision as a secondary or tertiary consideration.

In this same survey, 3 out of 4 mattress shoppers said they thought mattresses were expensive or somewhat expensive. But surprisingly, getting a ‘sale price or special deal’ was not their top priority. When we asked them what would get them more comfortable with the price of a good mattress, the number one answer was consumer reviews. A special deal was the number two selection. And number three was independent expert recommendations. So, if you look at number one and three together, you find that what they most value is third party validation. People are saying, ‘I’m willing to pay this price for a mattress as long as you can show me other consumers who confirm that this thing lasts for ten years. Or, show me an independent expert who has no vested interest in the outcome of this sale who says this will provide the right support for me.’

“Where the specifications fit in, is that they’re something factual that salespeople can use to try to overcome the skepticism that consumers have during their mattress purchase process. The salesperson can say, ‘Hey, don’t believe me. This mattress has three-quarters inch of five-pound density memory foam, which is really high quality foam. If you don’t believe me, believe this fact.’

“We also asked, ‘are you confident about buying a mattress?’ and then followed-up with a question about what would get them to be more confident. Overall, twelve per cent of mattress shoppers chose detailed specs as their number one answer. It’s interesting to note that the least confident mattress shoppers are most likely to choose product specs as the number one thing that would increase their confidence. So, the very confident people are just looking for the best price. But the less confident they are, the more they are seeking objective information like independent expert recommendations, detailed product specs or consumer reviews.”

Given that GoodBed.com found that for most customers mattress construction isn’t their primary concern, Furniture World asked Magnuson at what point in the sales process a customer might want to know about components.

“Let’s say,” he replied, “that a salesman says, ‘Hey, this mattress is $1,200 and that one is $600,’ and the consumer lies on both of them and they feel the same. Then when she asks the salesperson, ‘Why is this one $600 more?’ she is told that it’s better quality. But she is skeptical. She is saying, ‘Well you’ve got to give me something more than that, because six hundred bucks is a lot more to pay just because you say it has better quality.’ At that point the salesperson has an opportunity to introduce any facts that substantiate this quality claim, including product specs.”

Some Customers  Want To Know About Bedding Components

“Most customers are trying to justify the price they are paying for their mattress,” continues Magnuson. “They want to get comfortable with the price, because they are interested in purchasing a good mattress. But they have a trust issue, so they’re trying to filter out things like opinions and benefits, which sound like spin to them. When they filter out the spin, they end up with specs. The problem is that most consumers can’t translate mattress specs into meaningful benefits on their own, so having this information often leaves them feeling rather cold.”

In addition to Michael Magnuson’s observation that customers are interested in construction features to find some facts they can trust, industry experts interviewed for this article noted that customers may have an interest in knowing more about components as the result of visits to other stores, internet research, brand advertising or social networking.

Bob Muenkel, Director of Sales Education & Development at Serta International agrees that, “They’re trying to educate themselves. “It’s really all about building their confidence in the outcome, and of course overcoming their fear of making a purchase mistake. The outcome isn’t necessarily buying a good mattress, the outcome is to sleep well and feel really great in the morning. So, they’ll latch onto whatever facts are easy to understand. But inevitably, there is much more to those facts about components than meets the eye, and absent the detail, customers are really not protecting themselves.”

“At some point in the sales process, construction does become important to many guests,” adds Cory Ludens, Director of Learning and Development for retailer Mattress Firm.

“It may be that a guest has cued in on a particular component such as memory foam, latex or a specific coil. I think that often, this interest is seeded either by research on the Internet, or a visit to another store. A friend or relative who owns a bed that has a feature they really like may have placed the idea there. But I think that generally they're looking for a comfortable bed. They're looking for a good value and for relief from a problem that they have. If there's a specific problem they have with their existing mattress, then they may be looking for a bed that has a component that helps to solve that problem.”

Let’s focus for a moment on the eight per cent of respondents to the GoodBed.com survey who said a knowledge of components would make them feel more comfortable with their purchase. Might they all be male, pocket protector carrying “engineer types”?

Brett Swygman, Director of Sales and RSA Development for Simmons Bedding Company comments that, “Those engineer types that ask what I would consider deep dive questions have done all the research, and come in with a folder full of papers. These people want to know the whys and the hows of the mattress.”

Mark Quinn, Segment Vice President Of Marketing at component manufacturer Leggett & Platt, Incorporated agrees, telling Furniture World that, “I’ve got friends that work in Houston, Texas where NASA is. These people want to know the gauge, the turn of the coil, the metallurgy composite. I think you have to measure every customer based on the questions they ask, the good qualifying you’re doing up front to really understand at what level they want to have a detailed spec discussion.

“But I’d say as a general rule you want to keep it all focused on the ultimate benefit the component can give the consumer. Maybe only explain the two different types of coils.
“But we have to be careful not to stereotype,” cautions Kurt Ling, CEO of Pure LatexBLISS. There are some customers that care more about specifications than others, that’s for sure. But it isn't just men, engineers with slide rules in their pockets. The web has enabled customers to do research before and after they start shopping, equipping them with a lot more information than they have ever had before. “

What Salespeople Should Know About Mattress Construction

“Retail sales professionals should know about the internal construction of the products that they sell,” instructs Mattress Firm’s Cory Ludens. “I believe it's important for retail sales associates to know and understand components so that they can be an educated resource for guests. I don't think that they necessarily need to be able to explain all of those construction elements to every guest, because some people, obviously, don’t care about that.
“I’m talking about things such as the kinds of foam, the type of inner spring system, how the mattress and foundation are built, and how the components are arranged to work together. They should know if there is an edge support system, and how it is made. Also, if there is anything noteworthy about the cover.

“Ultimately they should be able to guide guests through the decision-making process and help them to be able to make the right decision on the right product for them. So, just knowing this one has 300 coils and that one has 800 coils, isn’t enough. Knowing why a particular bed has 300 coils and the purpose those 300 coils serve, is important.”

Leggett & Platt’s Mark Quinn believes as well, that sales associates should know their components because, “Consumers are more discerning in how they approach buying products today. They’re not willing to just throw out money based on general discussions about what’s better. They want tangible information stated in clear-cut language about what makes a product better. So, we need to be able to have that discussion, whether it be on a website where we’re catching consumers in the shopping phase or, if they’re in the store.

“The number one reason consumers buy a new bed is because of comfort, and so we have to be realistic. But factors such as durability, or a $300 difference between two similar mattresses also come into play. A discussion of components can be a big part of that discussion. There is a the catch though. If we drag the consumer into an industry-speak kind of conversation we’re going to lose them. And, it’s not something we want to do because those consumers aren’t going to, number one, be interested or, number two, follow the conversation.”

W. Brent Limer, National Product Manager, Hickory Springs Bedding Products, believes that, “Now more than ever, consumers are becoming more educated. The Internet makes it easy to look up reviews at the touch of a button, they are able to see what types of components go into certain products, across the board. So if you are a retail sales associate and you don’t know the difference between a 1.8 pound foam and a one pound foam, then you need a little more education.

“Comfort is the key selling point, but if a mattress is only going to last a short period of time because of body impressions or defects, that is also a key factor, so that’s why the retail sales associate should understand construction. Maybe a customer can’t decide between two different models or even two different brands. If RSAs are knowledgeable enough to know what the specs are, they can utilize them in their sales presentations, particularly as they relate to durability, comfort or other customer concerns. It can end up breaking a tie because sometimes customers just can’t decide, and walk off without making a purchase.”

Retail Mattress Education

Moving into a discussion of how retailers can design programs to train this skill, Ludens continues. “We teach construction in a number of ways at Mattress Firm.

“So, let’s say we’ve received product construction information about a new bed. The next step is to talk about how we can convey that information to our guests, so we can explain why this particular product “X” is different, from product “Y” and why product “Y” might be better suited for their needs. Typically we rely on manufacturers to supply the information. Then we take that information, and build it into our training here at Mattress Firm.

“We also ask manufacturer’s representatives to conduct sales meetings and workshops. Training product knowledge is viewed as a shared responsibility.

“The most successful retailers really have in-depth, deep training departments,” observes Simmons Bedding Company’s Brett Swygman. “From a manufacturer’s standpoint, we are very good at providing product knowledge education. But sometimes retail sales associates focus too much on that product knowledge, causing them to over-sell. They need to resist the temptation to get into the nuts and bolts of sleep sets , and instead focus on customers and their true needs. It's all about providing a better night‘s sleep, allowing that customer to wake up refreshed. That's what customers want.”

When To Talk About Bedding Components

When we asked Simmons’ Brett Swygman about the best time to introduce information on components, he told us, “You want to wait a little bit until you are well into the sales process before you discuss construction. First, you need to qualify customers to identify their needs. When you get to the point where a consumer is starting to show interest in a specific product, at that point it might be time, at a high level, to discuss construction. Let me give you an example. The sales associate might say, ‘There are many technologies in the mattress industry. They keep evolving, and growing. There are some newer technologies and some different technologies out there that I'm going to be showing you today.’ And then the sales associate listens to see what the customer’s level of interest is, and can add, ‘Our sales process includes a comfort test.’ At that point the associate stops to identify what comfort is, and then goes into, at a high level, the different types of constructions. I don't think retailers should get into the nuts and bolts 100 per cent early in the product presentation, until they’ve identified what the customer’s needs are.”

Swygman gives an example of a good reason for not jumping in early, telling Furniture World that if a customer tested out, for example, a specialty product early on in the sales process, “They may not even like it. So, why would you go into a deep dive, telling them about memory foam? The minute you start going into these nuts and bolts,” he says, “consumers may start to get confused. And you don't want to confuse them. So, you really have to focus on their needs, and on the benefits that product is going to deliver. If the customer asks how or why a product is going to deliver that benefit, then that's when you want to get into the nuts and bolts.“Usually we present construction features toward the middle of our presentations," adds Mark Wells, Vice President Digital Marketing and Commercial Business at Montana based Sleep City. “It’s never something we lead with. We get a lot of customers who just want to feel comfortable, and that's when we say, ‘This new construction provides more comfort. You will have more freedom of movement, your weight distribution will be dissipated among multiple springs. And what this technology means to you is that you will feel comfortable.’ And, that will apply to whether they need more comfort in their hips, pressure points and back. Or, if they are a side sleeper, sometimes their knees.”

Asking The Right Questions Is Critical

Our experts were generally in agreement that customers have varying degrees of interest in finding out about components. Also, that presenting information on construction can move the sale along by resolving concerns about price, trust, and relative value. It can also support sales claims about comfort, therapeutic benefits and durability. Knowing this, it is plain that in order to present construction information in a skillful way, sales associates need to get information about what is relevant to their customers.

Addressing this topic, Brett Swygman, recommends that when salespeople, “position construction in the qualifying stage, they need to be focused on getting information about their consumers and their needs. Find out their past experiences,” he told Furniture World. “Some may have had a mattress for 10 or 15 years. They're having back pain and pressure points that’s causing difficulty in their lives. So, salespeople can collect a lot of information and words during the qualifying stage that will help them to position a feature or component as likely to solve their customer’s problem as soon as it delivers its benefit. Use this information and the words that they gave you early in the sales process and relate them back to the benefit and ultimately to the feature or features that deliver that benefit.

“If you find out that a customer is a side sleeper, for example and his hands become numb, or if he reports having back pain, relief could be delivered by a pocketed coil spring. Memory foam is also going to be a great component to bring up. It's going to deliver that pressure relieving benefit they need. It's also going to help to conform, and provide the enhanced support that many consumers with back pain are looking for.

“Also, keep in mind that the manufacturer’s goal isn’t to deliver one component or one feature in a mattress. We want to deliver an all-encompassing system to deliver that benefit. Those words that you listen to in the qualifying stage are a big deal. So when you use those words, be sure to talk to customers the way they talk to you. If they were very technical, then you talk technical. You want to mirror your customer.”

Sleep City’s Mark Wells, gave us another piece of advice about qualifying questions. “You really have to establish a rapport with the customer to make them feel comfortable,” he noted. “Once the customer has told you that they're looking for a new bed say, ‘What brought you in? Why are you looking for a new mattress?’ To that question, there are usually three responses. They may say that their old bed has body impressions, their back hurts when they wake up in the morning or it’s a comfort issue. Many of our customers have had back surgery or other injuries, or their old mattress has just gone south so they're looking for new things in a new mattress.

“Let's say, for example that if a customer comes in and says, ‘I want a firm bed.’ I like to put them on a firm bed and then start the process from there. They might say, ‘Oh, this is really firm.’ I then explain why it's firm and ask, ‘What are you looking for?’ If they respond, ‘Well, I like that support, but I don't want to sleep on a board,” I would ask what position they sleep in, if they've had any injuries and why they're looking to change from their current mattress. In that way, I can get more information about what's going on with that customer which opens up an opportunity to go into the different foams, innersprings or specialty bedding.”

Serta’s Bob Muenkel, told Furniture World, “We suggest that sales associates ask five questions that target the most common sleep problems consumers have. One of the questions, just to give your readers an example is, ‘Do you find yourself rolling towards the middle or off the edge?’ It’s a simple question. If they’re never rolling off the edge of the mattress, why would you talk about foam encasements. How would that be relevant to that consumer? Why would they even pay attention to you? Sales associates need to learn how to explain that technology in a meaningful way so that the consumer recognizes that the presented technology is a good solution to their problem.”

With regard to qualification questions, Kurt Ling of PureLatexBLISS, believes that it is important to find out how much information people really want to know. He suggests that sales associates first try to match up mattress features with benefits that are relevant to each customer. “For example,” he says, “we have a new climate control technology that’s about temperature regulation while a consumer sleeps. To find out if this feature provides a relevant benefit we ask the following questions in this order. First, ‘Would you or your spouse say you are either a warm sleeper or a cool sleeper?’ Second, ‘Would you be interested in seeing a mattress that can help you sleep slightly cooler or warmer depending on your need in the same bed?’ This second question asks permission to take them to a product that helps solve that problem. And third, ‘I can tell you about how this works if you would like. Would you be interested in understanding either the design or technology?’ Some retail sales associates don't talk enough about the benefits features provide,” he says. “Others tell more than consumers want to know. Some of the time, they talk about what they know rather than what the consumer wants to know. Questions are a great way to bridge that gap.”

Like Kurt Ling, Mattress Firm’s Cory Ludens also believes in asking permission to present component information. “What we teach at Mattress Firm, and what great sales professionals do,” he said, “is to confirm understanding by asking, ‘What I'm hearing is this. Is that accurate? Great. Would you like to see a couple of beds that have some components that may solve that problem for you, or may help to rectify that problem in your next purchase?’ From there, they can go into a presentation of those products. Again, probably still not going through every single component that's in that bed, but rather, cueing in on those components that are designed to help to solve a problem or serve a need that the guest has.”

Bedding Sales Presentation Techniques

Furniture World also asked our experts to share specific presentation techniques that sales associates can incorporate into their presentations. We received the following tips:

  • When talking about components, Simmons’ Brett Swygman counsels that it is best to just present them as the facts. “Whenever the sales associate is talking to a customer who is really concerned about the components in a bed,” he continues, “they need to take the position of a news reporter. If they're asking about coil count or what type of foam is in the bed, then they want to be direct, and to the point. They could say that the benefit is delivered because of this or that component, and then follow up with a demonstration. Hand customers a demonstration unit so they can touch it and feel it.”
  • “The most important thing that we can relate to our customers is that our beds are made up of components and these components are designed to provide a certain level of comfort,” Sleep City’s Mark Wells points out. “When a customer is testing beds for comfort and tells us that she wants, for example, a softer feel, that's when we can explain that a particular bed is soft because it contains foam with certain properties or has foam layers that give it a soft feel. At that point the customer can feel what that means to her. And if she would like something a little bit firmer, then we can show her the next model up that has a little more memory foam, or one that has a different coil system, and she will start to notice the differences.”

Bedding Features Tell. Mattress Advantages Sell.... More!

Bottom line in this discussion is the fact that, as Sleep City’s Mark Wells reminds us, “Features tell, benefits sell.” Beyond that adage, it is the advantage to each customer that
components and construction methods provide that are most relevant.

“Ultimately when we are talking about product specifications,” concludes Cory Ludens, “we teach our sales professionals to talk not only about features and not even necessarily about just the benefits of those features, but about the advantage that benefit provides. So, they might point out a feature of a particular bed such as viscoelastic memory foam. The benefit would be that memory foam is more pressure relieving, which allows the guest to stay in one position for a longer period of time. The advantage then is that the customer wakes up more refreshed, with less tossing and turning. To be able to talk about a feature is one thing, but to have the skill to take this understanding and convert it into an advantage for your guest, is much more useful.

“Our guests are shopping for solutions to needs they have, and memory foam isn't the solution. Being able to sleep at night is the solution. So, being able to convert that feature to an advantage that a customer will own if they purchase a particular product is persuasive.
“They're not buying the features,” Simmons’ Brett Swygman adds. “One of the things that sales associates do is put too much weight on the features. When a sales associate can effectively show the benefit, whether it's motion separation, pressure relief, how a product can provide independent back support, allow the customer to move freely within the product, and then wake up feeling refreshed -- that's where the proof is. That is the step that they really need to focus on.”

Final Advice

Serta’s Bob Muenkel, concludes his remarks by advising us to, “Imagine we have a room. The consumer walks in on one side of it with no knowledge of sleep and mattresses. We enter at the other side with all of our knowledge of sleep and mattresses. We’ve been taught to bring the consumer into the middle of the room by educating them. We’ve been told that the best way to get them to buy is to meet them in the middle.

“I would suggest that, instead of meeting them in the middle, our obligation is to bring our knowledge across the entire room in a way they can understand, without all the technical language. The consumer has no obligation to learn about sleep or our mattresses. Whatever their problems are, we should take this technology to them in a simple, understandable way and make sure that it’s relevant to solving their problems. Again, our obligation is to bring our knowledge to them, not to educate them to us.

“The people who know the most about technology, and who are most effective at bedding sales, are the ones who talk about it the least. Instead, they take that vast knowledge and explain it at a level that is relevant to the consumer and in a way that their customers can appreciate, understand and not feel diminished in the process. That’s the art.

“Sales associates should never talk about a specification unless it has relevance to a customer’s particular sleep problems. They should never talk about mattress ingredients that don’t apply to the customer.

“Also, how sales associates answer the question, ‘What’s the difference’ between mattress A and mattress B, is critical to making the sale. If the sales associate just gives them a litany of specifications, without explaining the relevance to their life and their sleep problems, and how this manifests itself into a better night’s sleep, they are wasting their time.

And finally, consumers, buy mattresses based upon body comfort, and wallet comfort. The sale is made when a consumer has high confidence in the outcome, and low fear of making a purchase mistake. So, I believe the conversation should be focused on them, their sleep problems, and their sleep experience.”

Glossary of Bedding Terms

The following glossary of terms is excerpted from Furniture World Magazine's Bedding Educational Guide first published in 1985. Updates to the glossary are necessary and will be forthcoming.

AIR BED: A vinyl mattress filled with air, usually covered with cushioning and ticking.

BONNELL COIL: An innerspring mattress coil with an hourglass shape.

BORDER ROD: Heavy wire that forms the outer edge of an innerspring unit. The border rod is usually clipped to the outermost coils and the ends of the helicals.

BOXSPRING: A boxspring is designed to support an innerspring mattress. A mattress and boxspring together comprise a sleep set (see innerspring construction).

BUILT UP FOUNDATION: A box spring supported solely by wood and foam.

CALIFORNIA KING: Abed that measures 72 inches wide and 84 inches long.

COIL COUNT: The number of innerspring coils in a mattress determined by multiplying the number of coils in a row by the number of rows. For mattresses with a foam encasement, the coil count is the same as if the mattress had coils going right to the border rod. For a more detailed discussion of coil count and coil density see Bedding Anatomy 102

COIL SPRING: Spirals of wire in varying heights, sizes and gauges which form the supportive structure of an innerspring mattress.

CONTINUOUS COIL: An innerspring mattress coil configuration where each row of coils is made from a single piece of wire.

CUSHIONING: Polyurethane foam, cotton felt or other materials that lie above the insulator and below the ticking in an innerspring mattress.

DECK: Also known as the pedestal decking or platform, the deck is a flat board which sits on a waterbed pedestal and below the frame.

DENSITY: The weight per cubic foot of foam. Density is independent of firmness but is considered an important indicator of foam quality. For a detailed discussion of density see Bedding Anatomy 103

DISH: An undesirable characteristic common with four and five inch low density mattress cores. When weight is placed in the center of a low density foam mattress, the corners rise and bow in response to the deep compression.

DOUBLE BED: Also known as a full or regular size, a double bed measures 54 inches wide and 75 inches long.

DOUBLE EXTRA LONG: A bed that measures 54 inches wide and 80 inches long.

FATIGUE: A softening or loss of load bearing capacity. A condition which is a cause of complaints with innerspring bedding and low density foam mattresses.

FIRMNESS RATIO: The measure of the tendency of a spring to become firmer as greater weight is placed on it.

FOAM: Polyurethane foam is used as cushioning and supporting material in bedding. Common types are Conventional Polyurethane, Viscoelastic and High Resilance foam. Many people also consider Latex a foam. For a detailed discussion of foam see Bedding Anatomy 103

FOUNDATION: see boxspring.

FUTON: A flexible, usually cotton tilled mattress which is often used as a dualpurpose mattress and sitting surface.

FRAME: A rigid support system enclosing and confining a water mattress.

FULL FLOTATION SYSTEM: A type of mattress that makes use of a wood or rigid frame.

GAUGE: The thickness measure of the wire used in innerspring mattresses. A lower gauge denotes heavier wire.

HELICALS: wire spirals that usually hold together adjacent rows of coil springs.

HIGH RESILIENCE: HR foam is a variety of polyurethane foam which is more supportive, comfortable and durable than conventional foams.

HYBRID: A mattress that includes construction elements from more than one type of mattress. For example a foam core mattress that uses micro-coils as part of the comfort layer.

IFD: Indentation Force Deflection is a measure of the load bearing capacity or firmness in polyurethane foams.

INNERSPRING UNIT: The spring and wire unit made up primarily of coils, helicals and border rods which forms the heart of an innerspring mattress.

INSULATOR: A tough fiber padding, wire or netting which separates innerspring mattress coils from the cushioning.

LATEX: A natural  product often used to make premium quality latex foam mattresses. For a detailed discussion of foam see Bedding Anatomy 103

OFFSET COIL: An innerspring mattress coil that has an hourglass shape and a squared off section at the top and bottom of the coil.  For a more detailed discussion of mattress coils see Bedding Anatomy 102

PILLOW TOP MATTRESS: A top finishing treatment where a big pillow of soft materials is sewn over the entire surface of the mattress.

POCKET COIL: Cylindrical innerspring mattress coils, enclosed in separate flexible fabric pockets. The pockets are attached to adjacent pockets.

PRESSURE POINTS: The points at which capillaries will close due to pressure against the body. This undesirable effect can be reduced by a mattress that supports evenly.

QUILTING: Patterns that are sewn into the mattress ticking. For surface softness, many manufacturers quilt the ticking to soft urethane foam of varying thicknesses.

RESILIENCY: surface liveliness and springback ability.

TEMPERING: Tempering or stress relieving of coils, helicals, border rods, etc., with heat or electricity assures that the wire will return to its original height after compression.

TICKING: Ticking is the outer fabric covering on a sleep set. These fabrics are often attractive prints or woven damasks.

TOPPER PAD: insulation and padding material that lies on top of the spring assembly in an innerspring mattress.
