This is THE unit you want for using your cell phone hands-free while driving. It doesn't mind being knocked around, sits comfortably on your head without getting in the way while not in use, and in the case of my own cell phone, makes it a whole lot easier for the other person to hear me. On this last point, people often complain that they don't hear me when I talk to them on my cell phone, but with this unit they can even hear me whisper.