It works, but I have some reservations about automobile usage.  I would definitely use this if going on a long trip or frequent long commutes if the area was in question.  I've never actually had that issue, so I may opt to get the home adapter kit for this to use at my house.  It's too darn cold outside right not to try this in my car, so I connected it to a USB port on my desktop computer.  I ran the antenna and put it up on the window sill, and my little LG flip phone went from two to four bars.  I wanted to try it on my BLU GSM radio based phone, but without a sim card it showed no bars before or after, but the fact that a six year old phone got a boost was a good sign it does the job.