features small size, high efficiency and high power.Features:Adopts two high quality TPA3116D2 digital amplifier chips.Sound quality is very good, high efficiency and amplifying power.50W*2+100W 2.1 channels(left/right channel and subwoofer channel), high efficiency and low-heat.Powered by DC 12-24V, wide input voltage.User can adjust the volume by themselves easily.Applicable speaker impedance: 4-8 ohm.Just connect the power supply and loudspeaker box, enjoy the pure digital music!Notice:This amplifier board must be powered by DC power(DC12-24V), it's better to use high-performance switch power. Don't use transformer!