This MP3 player wireless FM transmitter allows you to enjoy the MP3 music saved on your USB device in your car, truck, boat or RV. You can now enjoy your MP3 music collection without having to spend money to upgrade your car stereo. This device uses FM radio frequency to broadcast the MP3 file format from any attached USB device to a preselected radio channel on your FM stereo. Simply plug into the cigarette lighter outlet, press play, and your MP3\'\'s will automatically start playing through your car stereo. The FM frequency is adjustable, select the least interfered frequency between 87.7 and 88.9 MHz on your car stereo. Easy to install & play your music. Set your radio to a unused FM station from 87.7 to 88.9. Set dial on the MP3 player to match that unused FM station. Plug the MP3 player into the 12V cigarette lighter socket (light indicator will blink every 3 seconds). Connect your USB memory drive with .mp3 files to the MP3 player. Press play. The MP3 music will now play through your FM radio. Adjust the channel if there is any signal interference. Specifications: 1) Built-in FM transmitter to broadcast MP3 music to radio channel 2) One touch operation for your safety when driving in traffic 3) Adjustable frequency setting selection for clear reception 4) Supports all USB 1.1/2.0 flash drives & even USB MP3 players 5) Insert into your car or boat\'\'s 12V cigarette lighter socket Packing: 1pc/clamshell packing 25pcs/carton