Feature:  ● Upgraded 3 in 1 Transmitter Receiver.  ● Dual Output Mode TX+RX.  ● Bluetooth 5.0 + EDR.  ● USB 2.0 Power Supply.  ● Colorful LED Breathing Light.  ● No Driver Required.    Specifications:  Product Type:  Wireless Audio Transmitter/Receiver;  Color: Black;  Backlit System: LED;  Bluetooth Version: BT V5.0;  Wireless Distance: 20m;  Input Interface: USB 2.0;  Output Interface: 2* 3.5mm AUX;  Output Mode: TX (transmitter) + RX (receiver);  Size (L*W) :  50 x 30mm;  Weight: 25g;    User Manual Pairing Method:  1. Toggle the switch to TX side.   2. Plug the adapter into USB port, red light flashes.   3. Use 3.5mm audio cable to connect the audio equipment (for example, TV) and the adapter's TX port.   4. Turn on your Bluetooth headphones or other Bluetooth devices, your audio equipment will automatically pair with it, and the red light will stay on after pairing succeeds.   1. Toggle the switch to TX side.   2. Plug the adapter into PC’s USB port, red light flashes.   3. Turn on your Bluetooth headphones or other Bluetooth devices, PC will automatically pair with it, and the red light will stay on after pairing succeeds.   1. Toggle the switch to RX side.   2. Plug the adapter into USB port, blue light flashes.   3. Use 3.5mm audio cable to connect your audio equipment (for example, Car stereo) and the adapter‘s RX port.  4. Search for ‘M11’ on your phone’s Bluetooth list for pairing, and the blue light will stay on after pairing succeeds.    Note: Only one device can be connected at a time. A single adapter cannot transmit and receive audio at the same time, only as a separate receiver or transmitter. Phone calling is not supported. 3.5mm audio cable is used to transfer audio.    Package Included:  1 x USB Bluetooth 5.0 Audio Transmitter Receiver,  1 x 3.5mm Audio Cable