The 4-channel GM-X374 features Pioneer's PWM-regulated MOSFET power supply and DMOSFET output circuitry for 400 Watts (max.) of big, efficient power with low distortion. A bridgeable 2/3/4-channel capability gives you system flexibility, and a built-in selectable crossover makes your install much easier. Speaker level inputs (4-channel) provide added control, and the "New Retro" aluminum vertical heat sink and high-volt (200mV-6.5V) input level control both improve performance. RCA inputs (4-channel) and outputs (pass-through) are included.