Convert your car cassette player to a high tech music player with the Cellet Cassette Audio Adapter. Specifically designed for the cassette player in your vehicle, this adapter allows you to play music whether on your iPhone, MP3 or CD players. The adapter is powered by the car"s electrical system so no batteries are necessary to operate it. Simply insert the cassette into the cassette player, plug the 3.5mm connector to your phone or MP3 player and press play.