Specification: Item Type: Digital Amplifier Board_x000D_Material: PCB_x000D_Operating Voltage Range: DC12-24V_x000D_Bluetooth Reception Distance: > 8m/26.2ft_x000D_Bluetooth Version: 4.2_x000D_Sound Source Input Sensitivity: 600-800mV_x000D_Frequency Range: 20Hz-20KHz_x000D_Speaker Impedance: 4-8_x000D_Output Power:_x000D_Power 12V 8 Speakers> 10W x 2, 12V 4> 15W x 2_x000D_21V 8> 30W x 2, 21V 4= 50W x 2_x000D_24V 8> 35W x 2, 24V 4> 60W x 2 Features: 1DUAL CHANNEL OUTPUT: Digital amplifier board is a DC12?24V single power supply with for TI's TPA3116D2 high performance digital power amplifier chip as the core, which can support 50W dual channel output. 2BLUETOOTH 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. 3POWER 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. 4EASY 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. 5SOURCE 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. PackageList: 1 x Digital Amplifier Board 4 x Nut 4 x Studs 4 x Washers