Precision Power i520.4 520-Watt 4-Channel iON Series Class D Full-Range Digital Stereo Bridgeable Amplifier RMS Power Rating: 4 ohms: 100 watts x 2 chan./2 ohms: 130 watts x 2 chan./Bridged, 4 ohms: 260 watts x 1 chan. Pulse Width Modulated MOSFET power supply LED power (green) and protect (red) indicators 3-way protection circuitry (thermal, overload, and speaker short protection) Balanced signal input