Zapco ST-5X II 5 Ch Class A/B AmplifierFeatures and Functions 5 Channel, Full Range, Class A B Variable input gain control Variable electronic crossover Auto on with Speaker level inputs Compact chassis Variable bass boost control Specifications Power @ 4: 4 x 100 watts Plus 1 x 200 watts THD @ Rated Power < 0. 5%THD Power @ 2: 4 x 150 watts Plus 1 x 300 watts Power Bridged @ 4: 2 x 300 watts RMS Plus 1 x 300 watts Signal to Noise Ratio > 95dB THD + Noise < 0. 5% Channel Separation >60dB