Features: 1) High fidelity, stereo: This device can modulate the audio frequency signal of CD, MD, MP3, MP4, PDA, Notebook and PC to FM signal (87.0 - 108.5MHz). With the stereo tune you can enjoy listening high quality music anywhere 2) Digital PLL: With digital PLL, wave signal transmission and reception will not be affected even in places subject to extreme change in temperature. In addition, using the digital tune can avoid the fussy frequency modulation 3) Powered by batteries or car power source 4) Full frequency range design can effectively avoid interruption 5) Power supply for MP3 How to use: 1) Install the batteries (2 x AAA batteries) or connect to car power source 2) Plug the FM transmitter into the audio device output port 3) Adjust the volume and frequency of the FM radio (avoid the transmission points of the broadcasting stations) 4) 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) 5) Press "O" button for a few seconds until M0, M1, M2...M9 is shown on the LCD, so that you can save the transmission frequency (If no battery on battery box "no power" can keep the stock and stock 10 years) 6) The FM transmitter will automatically shut down after 2 minutes if no audio frequency is input Specifications: 1) Frequency response: 20Hz - 20kHz 2) Separation: ≥50dB 3) Operating current: 50mA 4) Stand-by current: 90μA 5) Transmission range: 87.6 - 107.5MHz (interval 0.1MHz) 6) Power source: 2 x AAA batteries or car power source 7) Connecting cord length: 190mm 8) Accessory: 1 car charger Notes: 1) Because of the transmission the FM signal may sometimes be interrupted 2) When not using this item for a long time, please take off the batteries 3) The specification may change when we improve this product, then we won't give other notice