Bluetooth version: V3.0 + EDRKey features: Car MP3 playerSupported Card: Micro SD / MMC carSupport 16G expansionSupported format: MP3, WMA (option), WAVFrequency response: 20Hz-20KhzUSB port current / voltage: 2.1A / 5VBluetooth transmission distance: About 5 metersFM transmitting frequency: 87.5-108.0MHzWith LED screenThe environment temperature for operating: -10-70 centigrade The environment temperature for storage: -20-80 centigradePlug the item into your car cigarette lighter, then it would be power-on automaticallyYou could search for the device via your phone and connect them or you could insert a Micro SD card and enjoy the music via the itemPlease kindly try to tune the car FM to a frequency that don't have a station. Please adjust your transmitter and car radio at the same frequency to avoid noiseYou could enter into adjustment mode by short pressing the frequency button and adjust the launch frequency point you needed by pressing UP and DOWN button, and then confirmBest sound volume should be at 24 to 26Suggest adjust the volume to about 4 / 5 of the maximum volume, in order to avoid distortion of the soundอ่านเพิ่มเติม