This revolutionary Aux-Box connects to your factory radio and allows you to listen to an auxiliary source, such as an MP3 player or DVD player, through the head unit. No more sound-degrading FM modulator or clumsy cassette adapter. Get clean, high quality sound playing through your factory radio. The Aux-Box mimics a CD changer and “tricks” your radio into playing the auxiliary source. Not compatible with factory multi-disc CD changer.