Product name: 2.1 channel bluetooth audio power amplifier module Product model: -MT21 Bluetooth version: 5.0 (unblocked, 15 meters) Input Sensitivity: 500mV Input : AUX+Bluetooth Number of channels: 2.1 channels Adapter speaker: 20-100W, 4~8Ω Protection mechanism: anti-reverse connection, overheating and overcurrent, short circuit protection Adapter power supply: DC12~24V/5A or above (24V battery pack cannot be connected) Output power: left and right channels Less than 50W, subwoofer Less than 100W : 1. Only when the audio input is sufficient and the power supply voltage/current is sufficient will there be enough output power! 2. The higher the power supply voltage, the greater the output power, the smaller the speaker impedance, the greater the output power! 3. Please that the power of the adapted power supply is the actual working power of the power amplifier! Material: PCB+Metal colour: black Package Contents: 1 amplifier board 1 x screwdriver 1 adapter Only the above package content, other products are not included. Note: Light 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.