Features: 1) Build-in MP3 format decoding chips 2) 7 clear channels for choosing 3) FM transmitter can automatically read the MP3 format files from USB flash disk or MP3 player and audio port for iPod or PDA 4) Operating distance: up to 30m 5) Channel isolation ratio: e=72dB 6) Frequency range: 20Hz - 15kHz 7) Working current: 45mA - +10mA 8) Dual LED indicating 9) Output current: 100mA max. 10) Size: 10.5cm, 5cm remain long after plugging into cigarette lighter 11) Unit weight: 31g 12) How to use: a) Plug the FM transmitter into cigarette lighter of your car b) Plug the USB flash disk 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, ok, enjoy it f) You can turn off the FM turner and plug the headset into audio port, enjoy music yourself (only OT-FM09) f) Except USB port, you can connect others music players by audio cable (included), such as MD, mobile, PDA, Walkman (only OT-FM09) 13) Channel range: 87.7 / 87.9 / 88.1 / 88.3 / 88.5 / 88.7 / 88.9MHz or 106.7 / 106.9 / 107.1 / 107.3 / 107.5 / 107.7 / 107.9MHz