I really didn't expect this gadget to work but it does offer some improvement.  Here's the lowdown.  I live out in the country where cell service is questionable.  I have both a phone and a jetpack thing for my computer.  Both are frustrating to use.  So far I haven't really needed a signal boost in the car as most of the area I travel is a lot more reliable than home, but I do intend a trip this summer through some mountains that could pose a problem.  I have tested the cell booster both in my car and in my house.  The boost in computer internet connectivity is great as long as you're careful about plugging it in.