Morjava BC06S Car Bluetooth FM Transmitter with MIC Dual USB Type C + USB Flash Drive MP3 PLAY Car Charger Bluetooth Car Kit Voltage Detection 1. Volume up/down, / CH+ CH- /. Power indicator lamp / LINE input hole 2. The frequency display / car battery voltage display / load current display 3.. Answer/redial/Play, Pause . Microphone . Hang up/CH Mode/ Volume mode 4. LED display window 9. Power adaptor 12V-24V /. USB data input / USB output 5V / 2 .1A (maximum) 5.Dial the number by pressing the phone number under connection state and the sound will be given out from car audio.