The Punch 500-12P is a self-contained subwoofer enclosure with built-in amplifier. This "all in one" solution is great for systems that need extra Punch on the low-end of the frequency spectrum. The 12" high output subwoofer is impedance optimized for the built in 500-watt class-D amplifier that features a low-pass crossover, bass EQ and phase switch. You can change the amount of bass on the fly with the included remote level control. The slot port provides powerful output at lower frequencies for enhanced bass reproduction.