Adapted power supply: The working voltage range is 12-30VDC, and it is recommended to use a DC power supply with a voltage of 24V-28V and a current of 10A or above. Protection mechanism: Input undervoltage, input anti reverse connection, overheating, overcurrent, short circuit protection. Product name: 2.1 channel BT Amplifier Board 100W+100W+200W Product model: -APTX1 Maximum power: Left or right channel- 105W@30V , 4Ω; 55W@30V , 8Ω. Subwoofer- 208W@30V 2Ω; 105W@30V , 4Ω. In short, the higher the voltage, the smaller the resistance, and the greater the output power. Adapted speakers: Left and right channels, supporting 3-8 ohms and speakers up to 100W; The subwoofer supports 2-8 ohms and speakers up to 200W. BT chip: QCC3034, transmission distance of 15 meters. Input method: BT+AUX, BT priority, BT needs to be disconnected when using audio cable input. Number of channels: 2.1, Left and right channels+subwoofer Power amplifier chip: Two TI TPA3221 type: A-without shell Material: plastic colour: Black Package Contents: 1 x 2.1 channel BT Amplifier Board 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.