Alpine PDX-5M 5-Channel Power Density Digital Marine Class D Amplifier 4 ohms - 75 watts x 4 chan. + 300 watts x 1 channel 2 ohms - 75 watts x 4 chan. + 300 watts x 1 channel Bridged, 4 ohms - 150 watts x 2 chan. + 300 watts x 1 channel DC-DC PWM (Pulse Width Modulated) power supply LED power and protection indicators