Deliver the power your amp deserves Crutchfield's 4-gauge amplifier wiring kit contains the wire and hardware necessary to supply power to your amplifier safely, efficiently, and economically. This wiring kit does not include RCA patch cables or speaker wire . You may need to purchase those items separately, in order to complete your installation. Power ratings and amp efficiency Most amplifiers come in two distinct "Classes" of technology with different efficiencies and power wire size requirements. Class AB amps typically feature 50% to 60% efficiency, while Class D amps are usually 75% to 80% efficient. This Crutchfield wiring kit was designed to accommodate the energy demands of a Class AB amplifier with a total output of up to 700 watts RMS, or a Class D amp with up to 1,100 watts RMS output. Crutchfield wire Crutchfield wire is made of oxygen-free copper, with no impurities that could raise its resistance to a signal's flow or add interference. Crutchfield wire meets all Consumer Technology Association (CTA-2015) standards for size, resistance, and insulation quality .