do signal boosters for cell phones really work? which ones?

Answer 1

Absolutely. The ones you see here will really work and really work well. http://www.wilsoncellular.com/ However, it will cost you! But, it will give you the power of a 3W phone and external antenna for your car or home and your phones reception will benefit immensely.

Now, if you meant one of those little stickers that go underneath your battery, those are a gimmick and don't work.