Soundstream STL4.320 4-Channel A/B Amplifier (Black) RMS Power Rating: 4 ohms: 50 watts x 4 chan., 2 ohms: 80 watts x 4 chan., Bridged, 4 ohms: 160 watts x 2 chan Full MOSFET Power Supply Double side PCB and SMD components 3-Way System Protection circuitry (thermal, overload, high/low voltage) Black anodized finish w/ chrome accents