2.1 channel amplifier board 1. The remote control, U disk, and AUX terminals have been connected to the Bluetooth amplifier board. The corresponding plugs must be inserted and the line functions can be matched to work. You cannot solder lines yourself, and there is a risk of burning the Bluetooth chip.2. and supply: regulated switching supply: up to 20V; 12V supply maximum 2*15+30W 4; 20V supply maximum 2*25+50W 8Product name: 2.1 channel subwoofer amplifier boardSupply voltage: 12-20V DCSupply current: 3-5AMaximum : 2*25W+50W 8Minimum : 2*15W+30W 4-8Bluetooth version: 5.0Channel: 2.1Job type: Class DProduct size: 96 x 48mmcolor:BlueMaterial:PCB+MetalPackage Contents:1 x Bluetooth amplifier board1 x remote controlOnly 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.