Hifonics ZRX2000.4 Car Amplifier A/B Analog Class Amplification that is Blue "Military Grade" PCB High Dissipation Heat Sink that is 4/2 Ohm Stable High Speed MOSFET Output Devices Multi Channel 4/3/2 Channel Configurable with Variable Low Pass High Pass and Band Pass PWM Power Supply RCA Inputs/Outputs and Built-in system Diagnostics