Features: 1) Built-in MP3 decoding chips 2) 7 channels for choices 3) FM transmitter can automatically read the MP3 files from USB flash disc or MP3 player 4) Operating distance: up to 30 meters 5) Channel isolation ratio: ≥72dB 6) Frequency range: 20Hz - 15kHz 7) Working current: 45mAh ± 10mAh 8) Dual red LED indication 9) Operating frequency: labeled on unit 10) Output current: max. 100mAh (according to different models) 11) Sizes: 10.5cm, 5cm 12) Remain long after plugging into the cigarette lighter 13) Weight: 45g 14) Connect to your audio players, including MP3, MD, CD, PDA, portable DVD players, walkmans and laptops, the device can set up digital play, car or home audio system wireless link quickly and easily 15) Instruction: a) Plug the FM transmitter into cigarette lighter of your car b) Plug the USB flash disc or MP3 player into the USB port c) Press the CH button to select frequency d) Turn on your FM turner of your car, choose the frequency which the same frequency of the FM transmitter e) Adjust volume to proper level, press Play button once f) You can turn off the FM turner and plug the headset into audio port (OT-FM09) g) In addition to USB ports, you can connect other music players by audio cable (included), for MD, mobile phone, PDA, and walkman (OT-FM09) Inner packing: 1pc/gift box or blister