With DC isolation, 12V power supply With DC isolated power supply: suitable for retrofitting speakers, power amplifiers, and car-mounted Bluetooth functions, perfectly solving common ground current noise and noise 2 mobile phones can be connected at the same time (: automatically return to the last paired 2 mobile phones when powered on) With call, Qualcomm, Bluetooth V5.0, , power on, the default volume is maximum. Using the amp chip, the sound quality is better GND and BAT: 3.7V lithium battery power supply (3.3V-4.2V) GND and VCC: select 12V power supply according to the DC isolation module L, G, R are single-ended outputs, which can be connected to input devices such as headphones, power amplifiers, and audio M+ and M- are the positive and negative poles of the microphone head COM is the common terminal of the button, and the other end of the button is connected to +, -, PREV, , PLY respectively Key Description: "+": short press to increase the volume, long press to continuously increase the volume "-": Short press to decrease the volume, long press to continuously decrease the volume "": short press the song "PREV": short press the previous song "PLY": short press to play/pause/answer/hang up, long press for 1 second to reject incoming calls Special function description: "PLY": long press for 3 seconds to force into pairing mode, long press for 6 seconds to clear the pairing list "PLY"+"+": Press and hold for 1 second at the same time to enter the search TWS mode "PLY"+"-": Press and hold for 1 second at the same time to enter the searched TWS mode "+"+"-": Press and hold for 1 second at the same time to disconnect TWS The appearance and color of different batches , which does not affect the use TYPE:QCC3008 APTXLL Receiver Board color:Green Material:PCB Package Contents: 1 x Module Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.