Parameters --- Working voltage DC 9V-18V, recommended DC 12V; maximum output 2x35W (18V/4Ohm); 4~8 ohm speakers can be connected. Properties --- Class , 2.0 dual channel. Input --- 3.5mm audio line input. Protection --- Input reverse connection protection; short circuit protection; overcurrent protection; overheat protection. Features --- Volume Adjustment Knob; Noble Black Gold Circuit Board; KEMET Speaker Capacitors, Channel Bulk Filter Capacitors; Black Copper Terminal Blocks; Gold Plated Audio Input Terminal Blocks. Colour:As shown Material:PC+Metal Package Contents: 1 x Amplifier Board Only the above package content, other products are not included. Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.