I bought this device because I wanted to use my MP3 in the car and although the idea sounds quite interesting the truth is this thing doesn't work. I tried every single frequency but nothing; there is a huge static noise all the time. I think I wasted my money. If you are looking for a way to connect your MP3 to you car stereo try one of those cassette adapters, they are cheaper and more reliable than this thing. By the way, I tried this thing with four different MP3 devices and ion three different cars, and the result was always the same: static and noise.