Description: Receiver USB Mode: The usb mode does not need to use 3.5 audio cables. It can be directly plugged into the car usb interface and speaker usb interface, and can be used directly after pairing with the mobile phone. Note: The car usb interface and speaker usb interface must support usb audio output. Receiver AUX Mode: AUX Mode needs to connect one end of the 3.5 audio cable to the kn318 audio interface, and the other end to the car 3.5 audio interface and speaker 3.5 audio interface, and it can be used after pairing with the Bluetooth of the mobile phone. Bluetooth hands-free calling Built-in microphone, when the mobile phone is talking, you can make hands-free conversation through the microphone on KN318, which is very convenient to use in the car. Specifications: Model: KN318 Technologies: BT5.1, A2DP, AVRCP Operation Range: Up to 10m / 33ft Pairing name:KN318 Pairing: blue LED flashing Paired successfully: The blue light keeps on Dimensions: 32mm*17mm*8.5mm Package Included: 1x Bluetooth 5.1 Audio Receiver Adapter 1x 3.5mm Aux Cable 1x User Manual  Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-Dadangjia