The Master Cables Cassette Adapter is designed for anyone who has a cassette player in their car who wants to play something other than cassette tapes. It includes all the bits and pieces you need to link your audio device to your car's stereo. You get a connection that's shaped just like a cassette tape that actually goes into the player. You get a lead with a 3.5mm jack plug that connects to the headphone jack or line out socket on your audio device.