Skar Audio RP-75.4AB 500 Watt Full-Range Class A/B 4 Channel Car Amplifier MOSFET 4-Channel Power Amplifier Max Power at 2 Ohms: 190 Watts x 4 Channels RMS Power at 2 Ohms: 115 Watts x 4 Channels RMS Power at 4 Ohms: 75 Watts x 4 Channels Class AB Circuitry, Variable LPF and HPF