I read the reviews before I bought this product so I had an expectation that in my environment it would work correctly....and it did.  It's important that you can find a signal sweet spot...most likely outside of your house...that is within 30 to 50 feet of the area where you want to boost your signal.  For technical reasons you need a separation between where the receiving antenna is located and where you want to place the associated amplifier.  I was told by the tech dept you can locate the receiving antenna further than 50 feet away but there is a cost signal wise that is about 7db...appox 1 bar on most phones... for each 100 feet.  In my case the cable length needed to be 62 feet (I had to put a 12 foot extension on the 50 feet supplied) to allow my receiving antenna to be in the best sweet spot I could find on my property.  The sweet spot was a location that was between -82db and -85db which is about 4 bars on most cell phones.  The line of sight is about 30 feet away from my inside problem area but in order to run the cables I needed about 62 total feet of cable.  The end result was that although my cable needed to be longer...the signal strength at my sweet spot was way more than enough to offset the extra cable length signal loss.  The bottom line is I have a wonderful signal where I used to not be able to talk inside my house.  I placed the inside amp box near where I previously had no signal.  I recommend this product to those who have a sweet spot they want to "move" inside.  If you do not have enough signal anywhere then do not buy this product.  This product simply allows one to move the best signal to a new location...but that location has to be within a reasonable distance away.  One more note...it is very important to take a lot of time to find the best sweet spot you can find.  Most cell phones can be put in a mode where you can see the signal strength in decibels rather than bars....the lower the decibel number the better.  You need to know that it takes most cell phones 15 seconds or more to update those numbers so finding the absolute best sweet spot is not always fast.  Sometimes 1 foot movement can make a huge difference signal wise so take your time to locate where your receiving antenna should be mounted.  Also it helps to know where your cell phone transmitting tower is and point the receiving antenna towards that tower.  This might be a problem for some consumers to find but if you do know the direction of your cell phone company's tower you can fine tune signal reception in a fringe area.  I suspect that if you find a sweet spot of 4 bars or more the actual location of the tower will not be a huge problem but it certainly will help.  None of this is hard to do and it really makes a difference between getting a fantastic signal inside to just a marginal one.  The 30 day guarantee is great for those who cannot make this product work in their location.  Well worth the money.