No DC isolated power supply: suitable for lithium battery power supply, used to modify bluetooth headset With call, CSRA64215 low power consumption, 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) 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 Color: green Material: PCB COM is the common terminal of the button, the other end of the button is connected to VOL+, VOL-, PREV, NEXT, PLY respectively, and the length of the button line is within 5cm Key Description: "VOL+": short to increase the volume, long to continuously increase the volume "VOL-": Short to decrease the volume, long to continuously decrease the volume "NEXT": short song "PREV": short the previous song "PLY": short to play/pause/answer/hang up, long for 1 second to reject incoming calls Special function description: "PLY": long for 3 seconds to force into pairing mode, long for 6 seconds to clear the pairing list "PLY"+"VOL+": and hold for 1 second at the same time to enter the search mode "PLY"+"VOL-": and hold for 1 second at the same time to enter the searched mode "VOL+"+"VOL-": and hold for 1 second at the same time to disconnect Package Contents: 1 x Bluetooth Receiver Board 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.