Polk Audio PA500 4 4-Channel Bridgeable Power Amplifier 4-channel, dual bridge-mono (2-channel) power amplifier Power handling: 125 watts x 4 (2 ohm) continuous power, 250 x 4 (2 ohm) dynamic power or 250 watts x 2 (4 ohm) continuous power Double layer fiberglass epoxy printed circuit boards 6-way smart system protection (SSP) circuits High-speed MOSFET switching power supply