brand new and high quality. Features: This is a support Bluetooth-compatible 5.0 audio receiver Updated, with a pre-amplifier, Bass crossover Processing. With , left and right channel volume adjustment, treble adjustment, the total volume potentiometer control 2.1 amplifier board. Use for DC power supply: 12-24V Power Supply, Maximum support 50W (left channel) +50 for W (right channel) +100 for W ( channel) three-channel output. Use high-performance digital amplifier chip as the core, a parallel bridge subwoofer output, do a left and right channel output. Wide operating voltage, power-saving design, efficiency up to 90%. You can use good performance switching power supply, laptop switching power supply, you can also use the charging bottle, or car power supply and so on. Function switch Instructions for use: 1. Plug in the power on default Bluetooth-compatible mode 2. When Bluetooth-compatible Disconnected, Single Press switch can Change to audio Input Mode. 3. Bluetooth-compatible for play status, short press the switch to pause / for play. Specifications: Voltage Range: for DC 11-25V Subwoofer frequency range: 20Hz~200Hz Bluetooth-compatible receiving distance: > 8 for m Audio input sensitivity: 600-800mV Frequency response range: 20Hz-20KHz Speaker impedance: left and right channel speakers: 4-8 ohm Bass speaker impedance: 2-8 OHM Material: Metal and Plastic Size: approx.101x120mm/3.98x4.72in Color: As pictures shown Optional Styles: with Bluetooth-compatible / without Bluetooth-compatible / for Shell Quantity: 1 Set 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! Package Includes: Type A: 1 x Bluetooth-compatible Subwoofer Amplifier Board or Type B: 1 x Subwoofer Amplifier Board or Type C: 1 x for Shell (other accessories demo in the picture is not included.)