Features: 50Wx2+100W 2.1 channel power amplifier is easy to change, you can install and use it conveniently with wide compatibility. Supports reverse connection protections, overvoltage protections, undervoltage protections, overheating protections, and short circuit protections Equipped with volume control and power switches, it is very suitable for making passive speakers and home audio systems by oneself It uses copperDC connectors and barrier terminals. It can withstand high currents without generating heat or damaging wires Large area heat dissipation system, good quality module, which will not overheating and stop working during long-term high output Specifications: Item: ZK-MT21 2.1 Channel Audio Amplifier Color: Black Size: approx 93x90x22mm/3.66x3.54x0.87in Bluetoothcompatible version: BT5.0 Audio input: AUXand Bluetoothcompatible Channel: 2.1 Power: DC12-24V / 5A Adapter speaker: 20-100W, 4-8 Output power: max50W(right and left sound track), max100W(subwoofer) Package Includes: 1Set 50Wx2+100W 2.1CH Power Amplifier Board (the case needs to assemble) note: Due to the problems of lighting effects and shooting angles, there will be certain tolerances in the product, please understand. Please allow 0-1cm error due to the manual measurment.