No refitment to car.Put one connector of the tranimitter into the car lighter plug and the other connector into the earphone hole of MP3(CD,MD,etc.).Then set the car radio requency to FM107.7(±0.5MHz).The music inside MP(CD,MD,etc.) can be changed to frequency signal Automatically and sent to the car audio system.That Means to use the transmitter,you can listen to the Music inside MP3(CD,MD,etc.) from car audio system. Features: (1)Applied to all kinds of automobile.No refitment. (2)Imported chip,newest relief 3D digital technology and highly original (3)Using leading PLL technology,stable frequency and strong anti-interference function.