three-quarters; however, modern runners enable full-extension drawers. A slide's design parameters are its height, depth, extension, weight rating, durability, serviceability, and smoothness of operation. Soft close and push to open New varieties of hinges and slides have been developed that enhance the action and usability of doors and drawers. Soft Close is one of the most widely used hardware upgrade, a system where once a door/drawer is pushed to close, a mechanism slows the momentum of the door/drawer, closing it gently and quietly. This system is beneficial in reducing slamming doors, injuries to children and wear and tear on the cupboard. Push to Open is another common hardware option, this mechanism allows people to simply push the cabinet door, where a spring-loaded mechanism then opens the door without the need for handles. This option is used in high end kitchens where a clean, handle-less look is desired. Specialty hardware There is a large variety of specialty hardware for kitchen cabinets. Special hardware for corner and other blind cabinets makes their contents more easily accessible. They may be in the form of lazy susans with or without a wedge cut out or of tray slides which enable the hidden corner space to be occupied with trays that slide both laterally and forwards/backwards. Sponge drawers use special hinges that fit between the cabinet front and the sink. Buying cabinets Before buying cabinets, precise measurements are essential otherwise there may be un-utilized space, cabinets may not fit, or there may be interference between various elements of the kitchen, such as doors and drawers. Note that European cabinets typically have different sizes than ones in North America, and are typically built in multiples of 100mm, with 600mm wide being a common size. Buyers can buy pre-built "stock" cabinets for fast delivery which usually arrive in a week or less. In contrast, custom-made cabinets can have longer delivery times, such as four weeks. Base cabinets are usually deep and high to accommodate a countertop surface normally above the floor. Wall cabinets are usually deep. Their heights are often , for example, if mounted to a soffit. In a kitchen with ceilings, a wall cabinet will leave about of space above the cabinet which can be covered with a crown molding; a full wall cabinet will run straight to the top of the ceiling. Wall cabinets are sometimes called "upper cabinets." The distance from countertop to