Boss DST4000D 4000 Watt Class D Monoblock Amp: * MOSFET power supply * Variable low pass crossover * Variable subsonic filter * Variable bass boost 0 to +18dB * Phase selector: 0 or 180 degrees * Variable gain control * Input voltage sensitivity selector * Chrome plated RCA inputs * Line outs (for systems building) * Strapping capable * Power and protection LEDs