If this thing worked, I agree that it would only work in an open air environment. Its allot like the misunderstandings of how WiFi extenders work. While WiFi extenders don't boost your signal, they relay a signal further, this thing claims the opposite. This antenna is attached to the back of your phone, so it is in no way relaying signal to your phone. It is said to be a booster, but if the signal is so poor because you're indoors, how exactly does it get better signal than your phone to begin with?