Baitaihem 2.0 Channel Class T 2x50W Home Audio Amplifier 100W HiFi Stereo Amp Black The outside enclosure & knobs adopt full aluminium material Efficiency: 81% @ 50W, 4, 88% @ 25W, 8,Dynamic range: 100dB Rated output power: 2*50W HiFi AccessoriesHigh-fidelity Sound Come with DC Power Supply