Amplifier board size: 7.8x5.2CMFixing hole distance: 7.3x4.7CMBluetooth 5.0, support the serial port to change the name and password, support the button to turn off/on, support the serial port to change the volume of the prompt sound and turn it off, on, no call function, the default volume is maximumTX, RX, GND: TTL serial port configuration 9600, N, 8, 1At 24V4A, the maximum output is 2x50W, and the varies with the voltageSuitable impedance: 4/6/8 ohms8-26V supply, with reverse polarity protection, support notebook adapter supplyThe appearance and color of different batches may vary, which does not affect the useTYPE:Bluetooth 5.0 Amplifier BoardStyle: with Password 1234color: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 picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.