Support TWS pair box (2 wireless stereo speakers), no call function, Qualcomm CSRA64110 low power consumption, power on, default volume is maximum, self-boost 6.5V, lithium battery power supply to drive 4 ohm 5/6/8W speakers, Mono (left and right channels combined) VCC, GND: 3.3-4.2V (powered by lithium battery) SPK: Speaker (4 Euro 5/6/8W) : The common terminal of the key, the other end of the key is connected to +, -, PREV, , PLY respectively Amplifier board size: 4.35x3.6CM Key "+": 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 function "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 Material: PCB colour: Green Package Contents: 1 x Amplifier 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.