Feature:1. DUAL CHANNEL OUTPUT: Digital amplifier board is a DC1224V single power supply with for TI's TPA3116D2 high performance digital power amplifier chip as the core, which can support 50W dual channel output.2. BLUETOOTH SOUND RECEIVER: Digital amplifier module supports bluetooth sound receiver with external sound input connector. Bass, midrange, treble tritone potentiometer, function control switch, volume adjustment potentiometer.3. POWER SAVING DESIGN: Sound amplifier board is power saving and up to 90% efficient. You can use a good switching power supply, switching power supply for laptops, or you can use a rechargeable battery or car power supply, etc.4. EASY TO USE: Digital amplifier board is a soldered and tested finished board. Connect the speakers as shown, connect the proper power supply, connect a bluetooth sound device, or connect the correct sound input.5. SOURCE INPUT PLAYER: Dual channel digital amplifier board defaults to bluetooth mode, waiting for bluetooth sound devices to connect. In bluetooth disconnected state, press the volume potentiometer switch to switch to source input mode.Specification:Item Type: Digital Amplifier BoardMaterial: PCBOperating Voltage Range: DC12-24VBluetooth Reception Distance: > 8m/26.2ftBluetooth Version: 4.2Sound Source Input Sensitivity: 600-800mVFrequency Range: 20Hz-20KHzSpeaker Impedance: 4-8Output Power:Power 12V 8 Speakers> 10W x 2, 12V 4> 15W x 221V 8> 30W x 2, 21V 4= 50W x 224V 8> 35W x 2, 24V 4> 60W x 2.Package List:1 x Digital Amplifier Board4 x Nut4 x Studs4 x Washers