Now you can use your iPod, PDA,MP3, CD, cassette player, PC, or laptop to listen to your favorite tunes through any FM stereo receiver. Features: LED Display 3.5mm headphone jack on almost any portable audio player (Frequency response: 20Hz-20KHz Separation: ?50dB save Power: Operating current: 50mA ; Stand-by current: 90?A Transmission range: 88.0-108.0MHz (interval 0.1MHz) 4 channels Preseted Power source: 2 AAA batteries or 12v Car adapter (Car adapter included) Connecting cord length: 190mm Dimensions: D79.4 x W53.6 x H26mm Weight: 63g (NOT including batteries) Accessory: 1 car charger Powered by batteries or the car's power source. Full frequency range design can effectively avoid interruption. How to use: Install the batteries (2 AAA batteries) or connect to the car?s power source. Plug the FM Transmitter into the audio device?s output port. Adjust the volume and frequency of the FM radio (avoid the transmission points of the broadcasting stations). Press the power button of the FM Transmitter, tune the transmission frequency according to the reception frequency of the FM radio. (If the FM signal is interrupted, please set the frequency of the FM Transmitter and the FM tuner to the other frequency.) Press M1/M2/M3/M4 button for a few seconds until M1/M2/M3/M4 is shown on the LCD, so that you can save the transmission frequency. (Make sure the batteries have power.) The FM Transmitter will automatically shut down after 2 minutes if no audio frequencys input.