The device was tested in a stationary car and my bars on my phone went from 2 to 3 consistently when i plunged the unit in. As an added bonus it might have help my phones wifi reception. There are two big drawbacks. 1st there is an outside antenna that need to be placed on the center of your cars roof. Unless you have this device installed which should work there is wire hanging from your dash to your sunroof or window. 2nd my Samsung note 2 will not in the hold with its protective case.