• Plug the unit into cigarette lighter of your car directly • Plug USB flash dick into car MP3 transmitter • Press the CH button to select one that not interferes with local broadcasting station • Tune the frequency of your car's stereo to the same as the unit • Press the play button on the FM modulator to enjoy your music • Color: white, black • Size: 10.6 x 4.2 x 2.9cm • Voltage: 12V DC and 24V DC • Operating current: <100mAh • FM frequency: Full frequency • Channel switch: press the CH key to switch preset channel • Audio source: USB flash disk or MP3 player