No output filter required single-ended input "power on, power down" noise suppression No impact sound when switching Overcurrent protection, overheating protection, undervoltage protection Power supply voltage: DC12-18V Supply current: 3A Output power: 2x20W output Impedance: 4-8 ohm Noise : 98dB Voltage and power : Working voltage range: 12V-18V Output Power: 15W (CLASS D, 12V/4 ohm, =10%) 20W (CLASS D, 15V/4 ohm, =10%) Up to 92% efficiency (18V/8 ohm) The standard power supply is 12V, the current is 3A, and the maximum voltage is 18V (power supply 12V is not supported). It is recommended to use a 12V3A switching power supply for testing. Colour: green Material: plastic Size: 96 x 48mm Package Contents: 1 x Amplifier Board Note: Because this board has a bass tuning function, the maximum power is 2x20W when the full volume is turned on, and the volume may be attenuated during tuning Only need to be louder without distortion There is no manual, confirm the of Bluetooth USB circuit board connection placing an order. Only the above package content, other products are not included. Note: Light 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.