Dual USB fast charge speed up: dual USB ports charge at the same time, mobile phone and tablet charge at the same time will not affect the speed, more professional and safe charging certification. How to use:plug in the car cigarette lighter socket devices, turn on the car power;adjust the car stereo and the devices to the same blank channel,for example, if the car radio is 87.5MHz, the devices must be 87.5MHz, press the [CH] key Adjust the frequency;turn on the wireless of the mobile phone, search forBT-Car"and pair with it, the pairing is successful,the mobile phone music is played, and the sound is emitted from the car speaker. Description: This product is a player, dual USB ports are charged at the same time, mobile phone and tablet charging at the same time will not affect the speed,more professional and safe charging certification. Rated working voltage: DC12V-24V Working voltage limit: 9-26V USB1 output: 5V / 3.1A USB2 output: 5V / 1.0A Working temperature: 0-50 Support playback format: MP3 BT version: 5.0 version + EDR Wireless sound processing: A2DP (Advanced Audio Distribution Profile) Wireless transmission distance: 10M Effective range of wireless microphone: 0.5-2M FM transmission frequency: 87.5-108Mhz Package Included: 1 * Player(Without battery)