Adapted power supply: The working voltage range is 10-30VDC, with a limit of 31V. It is recommended to use a DC power supply with a voltage of 24-30V and a current of 10A or more. The higher the voltage, the greater the output power. Never connect to AC power, otherwise it burn out! Adapted speaker: 3-8 ohms, 20-100W in BTL dual channel mode; 2-8 ohms, 50-200W in PBTL mono mode. Heat dissipation method: Multi tooth heat sink. Gain selection: 2nd DIP switch 2nd gear selection, 28dB, 38dB. Bridging method: Turn off the power first, turn the No.1 dial switch to the ON position, and the output end R+L+is short circuited in parallel for output, while R - L - is short circuited in parallel for output. Product name: 100W+100W dual channel/200W single channel pure rear stage amplifier board Power amplifier chip: TPA3221 Maximum power: In BTL mode,2 x 70W 24V 4Ω ,2 x 100W 30V 4Ω ;In PBTL mode, 150W 30V 3Ω, 200W 30V 2Ω,110W 30V 4Ω Protection mechanism: Input undervoltage, overheating, overcurrent, short circuit protection.Input anti reverse protection Colour:Black Material: ABS Package Contents: 1 x 200W Bridged Mono Subwoofer Speaker 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.