Features: Rated operating voltage: DC12V-24V Working Voltage limits: 9-26V USB1Output: 5V/2.1A USB2 Output: 5V/1.0A , read USB Flash music. Working Temp: 0-50 Support Play format: MP3 BT Version: Version 5.0 + EDR Bluetooth sound processing: A2DP(Advance Audio Distribution Profile) Bluetooth transmission distance: 10M Bluetooth microphone effective range: 0.5-2M FM transmission frequency: 87.5-108Mhz How to use: 1. Insert the device to car cigarette lighter outlet, start the car for Power ON; 2. Tune the car radio and device to a same blank channel, such as if car radio is 87.5MHz, the device must be 87.5MHz to, press [CH] to adjust frequency; 3. Turn on the Bluetooth of phone, search "BT-Car" and Pair with it, pair successfully, play phone music, sounds will comes out from car speaker TF/USB Flash Music playing: If insert the TF card or USB flash drive, it will automatically play USB music; Long press [Answer] button to swtich music mode between USB/TF/Bluetooth modes Bluetooth mode: Short press [Answer] button: Answer / Hang up call; Long press[Answer] button: Reject call Double press [Answer] button: Redial last phone number