1. Multiple parameters for customers to choose from 2. Products using high-quality materials, quality assurance 3. AUX audio input, for /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, 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 volume plus, long continuous volume plus "VOL-": short volume down, long continuous volume down "NEXT": short song "PREV": short the previous song "PLAY": short to play/pause, long for 3 seconds to force into pairing mode, long for 6 seconds to clear the pairing list Special function description: "PLAY": long for 3 seconds to force into pairing mode, long for 6 seconds to clear the pairing list "PLAY "+"VOL+": and hold for 1 second to enter search mode "PLAY "+"VOL-": and hold for 1 second to enter the searched mode "VOL+"+"VOL-": and hold for 1 second at the same time to disconnect 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.