The HE 4 is a four-channel, 800W (Max) amplifier that can be bridged in dual mono as well for utmost flexibility; it is the ideal choice to upgrade your factory system: pre-amplified inputs as well as hi-level inputs offer the possibility for the HE 4 to be interfaced with any head units, including factory OEM systems. Real 12dB/Oct. continuously adjustable (40 to 400Hz) active crossover with Lo-Pass/Hi-Pass or Full Range settings on each pair of channels ensures the best acoustic performance of your car audio system especially in front plus subwoofer application. The advanced electronics and the optimized cooling system ensure the HE 4 to provide high power, even under difficult conditions.