Amplifier board size: 7.1x4.3CMFixed hole distance: 6.6x3.8CMBluetooth 5.0, support serial port renaming, support one-key TWS pairing, support AUX inserting TWS to without interruption, power on, the default volume is maximumTX, , GND: TTL serial port configuration 9600, N, 8, 1At 16V4A, the maximum output power is 30WAt 12V4A, the maximum output power is 20W8-22V power supply, with reverse polarity protection, support notebook power adapter power supplyBoards and devices, workmanship, sufficient materials, and qualityM+ and M- are the positive and negative of the microphone headThe appearance and color of different batches , which does not affect the useTYPE:Bluetooth 5.0 Amplifier BoardStyle: support call functioncolor:GreenMaterial:PCBPackage Contents:1 x ModuleOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.