Before I bought this I had to go outside to talk on my cell phone. I contacted my carrier and found which side of my house a tower was located on. I installed the outside antenna per the directions on that side of the house. I went from 1 bar inside my house to 4 bars. This really works. It boost the signal just as it says. When I bought this I kept all the packing material expecting to return, I didn't. It's still working great.