Description:Features:1, Power supply circuit adopts full bridge rectifier.2, Effectively eliminate the high frequency interference of AC power grid.3, Chip has high conversion rate and strong drive ability.4, Better performance,noise is very small.5, Can not use 12 V battery or DC directly as power supply.Specifications:Working Voltage: AC double 15 V (10 W)Audio Input: RCA socketsAudio Output: 3P terminalSize: 110 mm x 54 mm x 22 mmPackage includes:1 x Pre-amplifier Board DIY SetNote:1, The amplifier board can not use 12 V battery or DC directly as power supply. Power supply should be positive and negative double DC power sources, or special AC 12 V transformer power supply.2, This item need a power amplifier to drive speaker. 3, Please allow 1-3 mm error due to manual measurement. Thanks for your understanding.4, Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.