Input Power: DC DC6.5-15V (see the required output power setting), power adapter, switching power supply, battery can be, the recommended use of current in more than 3A. Bass output power: maximum 25W, 4-6 inch, 4-6 Ohm 20W subwoofer is recommended. Left and right channel output power: 6W+6W, it is recommended to use 2-4 inch, 4-8 Ohm 3-25W full frequency speaker. The above power requires about 13.5V power supply. The left and right channels use a low-power enthusiast audio dedicated chip YD1517P as an output stage, which really provides results. Potentiometer shaft center distance: 24mm potentiometer mounting hole diameter needs 7mm. Input interface: 3.5mm socket. Channels: 3 (2.1) Type:Home Amplifier Due to different batches, there may be differences in product appearance and printed text, which will not affect use. Colour:Green Material:plastic Package Contents: 5 x Amplifier board 10 x knobs(color send randomly,cannot choose the specified color)