Sound Storm Laboratories AE424 AERO 2400W 4-Channel MOSFET Amplifier with High/Low Crossover and Remote Subwoofer Level Control - Black/silver (Discontinued by Manufacturer) Two OHM stable Class AB 4-Channel Capable of Tri-Mode Operation Remote Subwoofer level control MOSFET PWM (Pulse With Modulated) power supply Soft turn-on circuit