Comsoon Bluetooth FM transmitter for car, wireless car kit with dual port car chargers the easiest way to add Bluetooth function to your car stereo system; the simplest hands-free solution to bring wireless audio to your existing car stereo and listen to your favorite songs. Safe for calling built with a high-quality microphone, totally free your hands, just press the phone call button and speak while you are driving with both hands safely. Two music play mode 1) Bluetooth connection automatically and simply paired your phone with this device via stable Bluetooth. Bluetooth sound processing a2dp, offers a comfortable stereo music playing. 2) MP3 player insert USB disk into the right USB port, then automatically play and transmit the MP3 files; playing music to relax your body and mind during your driving. How to adjust FM? 1) Choose your radio into a blank unused FM frequency (87.5-108.0Mhz); 2) adjust this FM transmitter to the same frequency: long press "call button", until LED displays flashes; rotate clockwise to increase the frequency, rotate anticlockwise to decrease the frequency. Specifications: material: ABS product input: 12v-24v charger output: 5v/2.4A&1a music format: mp3, WMA Bluetooth protocol: avrcp, hfp, a2dp screen display: LED digital display.