(The other USB port is designed for normal charging or reading U disk. Type: FM Transmitter. USB Wireless Bluetooth 5.0 Transmitter Receiver for Car Music Audio Aux Adapter. 3) 7 Colors LED Backlit Mode: Our FM Transmitter Bluetooth for car has 7 LED backlit lights including green, blue, red, light blue, light green, purple, blue and white, which can get a visually stunning display of colours, plus a clear screen, no blind spot, improving your driving safety in the dark or at night.