The Wireless FM Car Transmitter is a handy little gadget that plugs into any device with a 3.5mm stereo jack. Transmit music from any audio device to FM Radio. Includes 8 FM frequency settings. The Coby CA-739 Wireless FM Car Transmitter is not just another transmitter for your portable audio player. It adds an integrated cigarette lighter adapter that provides power to the device - no more batteries! Simply plug the transmitter in, plug in your portable audio player via the CA-739's line-in jack, tune your FM radio to one of eight selectable frequencies, and you are good to go! It's just that easy.