Air cooled heat dissipation,continuous full power output. Six high-capacity energy storage capacitors. High end HIFI grade sound quality, signal to-noise ratio of 90dB. Supports 2-8ohm speakers, powered by DC 18-50V Note: 1. The shipment does not include power and audio cables. 2. Input does not support AC power, must use DC power! 3. The input power cannot be reversed or exceed 51V, otherwise it burn out! 4. The fan performs a self check and stops normally after 1 second of operation. It only starts when the -ture exceeds 50. 5. Bridge not supported, left and right channels cannot be connected together! Colour:Black Material:Plastic Package Contents: 1 x Audio Amplifier Board Only the above package content, other products are not included. Note: Light reflection 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.