Bluetooth 5.0 AUX / RCA receiver / transmitter adapter Features integrated echo cancellation and ANC noise canceling circuit, beautiful purer stereo sound. improved signal transmission IC, connects faster and more stably. compatible with various audio formats. Bluetooth 5.1 low energy consumption.  Integrated battery, long life. easy connection, no app or driver needed. Power on / off: Press and hold the button for 5S to power on, the blue indicator flashes after power on. Long press the button until the 5S turns off and the blue light turns off after turning off. Auto power off function: the Bluetooth audio adapter will automatically enter sleep power saving mode after ten minutes without connection and the light will turn off. This product has a built-in rechargeable battery for standby and long time use term. Please fully load the product before using it for the first time. Charging time is 2 hours. The red light is on during charging and turns off when charging is complete. You can also play music while reloading. In the low battery state, the light will blink slowly. 3.5mm aux and RCA cables included, microUSB charging cable included