The Rockford PBR400X4D is a full-range 4-channel car audio amplifier designed for stereo front/rear systems that requires little space. The BRT (Boosted Rail Technology) is an ultra-efficient design that generates 400 Watts of power! The BRT also has a variable hi-level DC offset turn-on circuit for easy installation into any OEM system.FEATURES AT A GLANCE Full Range Class-D Differential inputs with high level auto turn-on feature 8 AWG power/ground connector C.L.E.A.N. input/output clip detection and indicator LEDs Real time output and power supply thermal sensing Rockford Fosgate proprietary protection Selectable Fixed 12dB/Octave Butterworth Crossovers Extruded aluminum heatsink Muted turn on Discrete surface mount technology Remote-Out feature when using high level inputs Compact design for stealth installations 1 Year Warranty CEA-2006 and CE compliant