The Rockford PBR300X4 is a full-range 4-channel amplifier designed for stereo front/rear systems that requires little space. The BRT (Boosted Rail Technology) is an ultra efficient design that generates 300 Watts of power! The BRT also has a variable hi-level DC offset turn-on circuit for easy installation into any OEM system.; MOSFET output stage 2/4 channel input switch 12dB/octave Butterworth crossover High level inputs Ultra compact chassis Variable 4-6 volt hi level DC offset voltage input turn-on control 1 Year Warranty