Fits:  Polk Audio 4 Channel Amplifier PAD40004 

Anodized extruded aluminum covers and rugged end caps and stainless steel hardware won't corrode in humid environments. Uses a Class D bridgeable high-speed MOSFET switching power supply for fast response and high efficiency. Runs cooler than conventional amps. Toroidal transformers help keep the amplifier's sleek aluminum extruded design under 2" tall while ensuring plenty of clean efficient power. Low THD's high signal-to-noise ratios rated at full power plus wide bandwidths for clean distortion-free sound. Thermal DC offset reverse DC voltage and short circuit protection.
Channel mode switch (ST/4Ch)-In the stereo position the amplifier will send the same signal to front and rear channels.
Watts per channel Not bridged: 200 watts at 2 ohms 125 watts at 4 ohms
Watts per channel bridged: 400 watts at 4 ohms