Feature: 1. USB mode does not need to use 3.5mm cable, directly plug into the car or speaker USB port, and can be used directly after pairing with phone Bluetooth. 2. In AUX mode, connect one end of the 3.5mm cable to the adapter, and the other end to the the car or speaker, and use directly after pairing with phone Bluetooth. 3. Built‑in microphone, you can make hands‑free calls through the microphone on the adapter, which is very convenient to use in the car. 4. Connect the speaker with a transmission range of up to 10m/32.8ft, enjoy the original sound. 5. Small, lightweight and portable, convenient for carry and storage, plug and play, easy to operate. Specification: Item Type: Bluetooth USB TransmitterMaterial: ABSColor: As Picture ShownSize: Approx. 32x17x8.5mm/1.3x0.7x0.3inWeight: Approx. 21.0g/0.7ozBluetooth Version: BT5.1, A2DP, AVRCP Use Distance: 10m Pairing Name: for KN318 Pairing: Blue LED Light Flashes Pairing Successfully: Blue Light Keeps on. Package List: 1 x Bluetooth USB Transmitter1 x 3.5mm Audio Cable1 x Manual Note: The USB playback mode can only be used when the car or speaker USB interface supports USB audio output