PM400X4 - Rockford Fosgate 4-Channel 400W RMS 800W Max Punch Marine Amplifier. Rockford Fosgate PM400X4 4-Channel Punch Marine Amplifier. In addition to 4-channel stereo mode, you can bridge both channels to create a high power 2-channel amp, or run stereo speakers on the front with subwoofers on the rear in 3-channel mode.
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