ST-4X P - Zapco 4-Channel 480W RMS Class AB Amplifier 4 Channel Class A/B Amplifier | RMS Power Rating: 4 Ohms: 100 Watts X 4 Chan. | 2 Ohms: 150 Watts X 4 Chan. | Bridged, 4 Ohms: 2 X 300 Watts Signal-to-nose ratio: &gt;90dB | THD + Noise 60dB 12dB HP/LP/Full Pass Crossover | RCA and Speaker Level Inputs | Variable bass boost control Frequency Response 15Hz to 30KHz 1dB | Input Sensitivity .25v to 5vA Compact chassis | Dimensions: 6.29"(W) X 11.8"(L) X 2"(H)