The FM Transmitter puts music from your portable music player, CD player, or PC through you FM car or home stereo. All you have to do is plug the fm transmitter into the headphone jack of your player or computer, tune your stereo or receiver to any clear FM frequency, then enjoy your music experience with more sound and fewer wires. An automatic on/off function turns the transmitter on when an audio signal is detected. If no signal is detected for a period of 60 seconds, your transmitter switches off, lengthening battery life while simplifying your life. The system features four programmable memory slots and a Mobile Power Cord that connects to your car's cigarette lighter to provide power for the transmitter.