Wireless FM Transmitter. 1) Universal wireless stereo FM transmitter compatible with any car any radio. a) Auto car FM system, that can play MP3, CD, PDA, Person Computer, car-TV, car navigation, etc.b) Home wireless music system, that can reduce the difficult to layout the wire or for any place that local in different place.2) 4 channels for choosing Channel range: 88.1/88.3/87.5/88.7/88.9MHz or 106.7/107.1/107.5/107.9MHz. 3) Frequency LED to indicate the current channel you select.4) Operating range: 30 meters.5) Dual power supply model: 2 x AAA batteries or by car cigarette light DC power.6) Accessories: DC power adapter for car.7) Operation introduction:a) Plug FM transmitter into your music player.b) Set FM transmitter and your radio to the same FM frequency. c) Turn on the FM transmitter and the music player.d) The music will be transmitted from the player to the FM radio wirelessly. e) Enjoy your music now. 8) Note: for best results, select a frequency that has the weakest or no signal from radio station