This product is blue-tooth car charger mp3 player for vehicle; Adapting professional-grade high-performance bluetooth module, built-in mp3/wma decoder chip make it capable of playing the music files in u disk, firing into the car stereo via wireless. Besides, during the bluetooth connecting, play the phones music and FM transmitter to Car Audio, perfect, as the calls incoming automatically switches to the speaker state, call end then automatically back the music player. So you do not do any modifications, easily enjoying the music and hands-free phone calls while you are driving.