Big, efficient power: the GM-D500M is a Class D amplifier, so you get massive power with less heat - and less distortion - than with a conventional amp. Its pulse width modulation (PWM) circuit efficiently outputs only the lower frequencies, so it's perfect for powering subs. More good news: all this power comes in a small chassis, saving space for your install. It includes a MOSFET output section, screw-type speaker terminals and oversized power/ground terminals, and a die-cast aluminum heat sink. Plus, the built-in variable crossover cuts down on install time.