1. Multiple parameters for customers to choose from 2. Products using high-quality materials, quality assurance 3. AUX audio input, Qualcomm for APTX/ATPXHD programming, power on, the default volume is maximum, the volume of the alert tone is moderate 4. Support Android APP to modify the Bluetooth name (support Chinese), pairing password, custom EQ 5. Product performance is stable, long life Product description: B: DC isolated 5V power supply 4.5-5.5V 1, no DC isolation power supply: suitable for lithium battery power supply, used to modify the Bluetooth headset 2, with DC isolated power supply: suitable for modifying speakers, amplifiers, car to increase the Bluetooth function, to solve the common ground current sound, noise KCOM for the common end of the keys, the other end of the keys are connected to VOL+, VOL-, PREV, NEXT, PLAY, key line length of 5cm or less Key Description: "VOL+": short press volume plus, long press continuous volume plus "VOL-": short press volume down, long press continuous volume down "NEXT": short press the next song "PREV": short press the previous song "PLAY": short press to play/pause, long press for 3 seconds to force into pairing mode, long press for 6 seconds to clear the pairing list Special function description: "PLAY": long press for 3 seconds to force into pairing mode, long press for 6 seconds to clear the pairing list "PLAY "+"VOL+": press and hold for 1 second to enter TWS search mode "PLAY "+"VOL-": press and hold for 1 second to enter the searched TWS mode "VOL+"+"VOL-": press and hold for 1 second at the same time to disconnect TWS Colour:Black Material:Plastic Package Contents: 1x Bluetooth Music 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.