Features: 100% brand new and high quality Mini version 50Wx2 Bluetooth-compatible digital power amplifier board (volume control knob with switch). The potentiometer adjusts the volume with a switch for easy volume control, making it ideal for DIY speakers. If it is a metal box, you need to bring out the Bluetooth-compatible antenna. The DC connector copper is used to withstand high current and no heat. 470uf35V capacitor solid state capacitors ensure power storage and heat dissipation, and stable power supply is a prerequisite for good sound quality. Free DC lead head, compatible with the power input interface of this product, even if you do not have a DC adapter or battery head, it can be easily connected. 5.0 Bluetooth-compatible version, the transmission efficiency is higher, the transmission distance is farther. Precautions for use: The power switch on the board is the standby switch. After the switch is turned off, the machine is in a low-power standby state. Completely turn off the power or disconnect the DC plug on the machine for a long time. Package Includes: (A/B Optional) A: 1PC x Digital Power Amplifier Board with Shell B: 1PC x Digital Power Amplifier Board Specifications: Product name: Bluetooth-compatible digital power amplifier board 50Wx2 Product model: ZK-502L Adapted power supply voltage: 5~24V (9V/12V/15V/18V/24V and other adapters optional , high power recommended high voltage) Adapted speakers: 30W~200W, 40, 80 Number of channels: left and right dual channels (stereo) Bluetooth-compatible version: 5.0 Bluetooth-compatible transmission distance: 15 meters (unobstructed) Protection mechanism: self-recovery overheating protection, self-recovery short-circuit protection Colour:Black size:approx. 5.5x3.8x1.7cm/2.17x1.5x0.67in note: Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you