This product is a special Bluetooth car charger with MP3 player, adopts professional high-performance Bluetooth module, built-in MP3 / WMA decoder chip that can transmit music files inside the USB disk to car stereo via wireless, and can switch an incoming call to the hands-free state as long as your mobile phone is provided with the Bluetooth function. When the call is finished, it will be switched to the music play automatically. It can also send the music in your phone to your car sound wirelessly. You can enjoy the music and answer the call in hand-free mode without refitting your car, which ensures the driving safety while enjoying music. Features: - Support line audio input. - With power on / off switch ( USB direct connect ). - Support USB disk player. - Support MP3, WMA format music. - Bluetooth answer, hang up, reject, redial calls and other functions. - Bluetooth stereo music play. - Echo cancellation and noise suppression ( CVC ) technology during a call. - Support dual USB output voltage, the maximum output 5V / 2A. - Automatic power-off memory function. Special Function: MP3 Player, Hands-free calls, Bluetooth, FM Transmitter Features: Controllable power switch, Breakpoint memory playing Voltage: 5V Working Voltage: 12V Music Source: Flash drive, Cellphone Degree of Distortion (%): < 0.1% Freq. Response: 20Hz - 15Khz Bluetooth Version: 2.0 Bluetooth Protocol: A2DP Transmit Distance: 10 - 15m Media Format: Mp3, WMA Package weight: 0.085 kg Product Size (L x W x H): 11.5 x 2.5 x 2 cm / 4.52 x 0.98 x 0.79 inches Package Size (L x W x H): 12 x 5 x 2.5 cm / 4.72 x 1.97 x 0.98 inches Package Contents: 1 x Bluetooth FM Transmitter Car Charger 1 x Audio Cable 1 x English User Manual.