Features: brand new and high quality This is a 12-24v DC powered power supply, using ti TPA3116d2 high performance digital power amplifier chip as the core, one to make parallel low channel power amplification output, one to make output of left and right channel power amplification. Supports three channel output of 100w(left channel) 50w(right channel). Support bluetooth-compatible 5.0 audio reception, external audio input interface, with preamp, crossover processing; volume, frequency, left and right channel volume, treble, function/total volume control switch, 5 adjustment knobs. Wide working voltage, energy saving design, efficiency up to 90%. You can use a good performance switching power supply, laptop switching power supply, you can also use a charging bottle or car power supply, etc... The board is a finished board that has been soldered and tested. Connect the speaker box according to the picture, connect the appropriate power source, connect the bluetooth-compatible audio device to for play or connect the input of sound source correctly. This technology allows the device to maintain ultra-low distortion throughout the audio frequency band while exhibiting perfect sound quality. Specifications: Model: TPA3116 Power: 2x50w + 100w Size: 100x100mm/3.94x3.94in Operating voltage range: DC 12-24V(3-4A or 19-24v/4-5a current, as high power requirements 20-24v/8-9a above), Recommend DC24v 4.5a power supply. Note that the no-load DC voltage must not exceed 25.5v. Bluetooth-compatible distance:> 8 for m(Meter) Audio input sensitivity: 600-800mv Frequency response range: 20hz-20khz Bluetooth-compatible version: 5.0 Subwoofer cutoff frequency: 26-160hz Speaker impedance: Left and right channel speakers: 4-8 ohm Bass speaker impedance: 2-8 ohm Package Includes: 1Set x Digital Power Amplifier Board note: No retail package. 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!