2 in 1 Bluetooth Transmitter Receiver Wireless Stereo Adapter for TV Car Audio RX Mode Pairing: Turn on the device. Blue light flashes quickly. Then turn on the phone Bluetooth setting and search for Bluetooth device to select and pair connections. Insert the 3.5mm audio into the RX port to connect the transmitter and receiver device. You can enjoy the wonderful music TX Mode Pairing: Turn on the device. Then turn on the receiver device (Bluetooth speaker, Bluetooth headset, and other Bluetooth enabled audio system ) and wait a few seconds. The device will connect with the BT transmitter automatically. Then insert the 3.5mm cable into the TX port and your transmitter device (MB, TV, PC, MP3/MP4 those don’t have the Bluetooth function). Finally, you can enjoy the music. The Indication Light: The red light doesn't flash when you charge. The red/blue light flashes quickly when the device is on transmitter/receiver modern and don't pair successfully. the red/blue light flash slowly means pair successfully. Specifications: Technologies: Blutooth 4.2, A2DP, AVRCP (receiver mode only) Operation Range: Up to 10m / 33ft (without any blocking objects) Charging Time: 2 hours Continuous Use Time: 6 hours (Receiver Mode) / 5 hours (Transmitter Mode) Battery Type: Li-Polymer (200mAh) Dimensions: 44 × 44 × 12mm Packing  List: 1* Bluetooth Audio Transmitter/Receiver Adapter 1* Micro USB Power Cable 1* RCA Cable 1* 3.5mm Aux Cable 1* User Manual