100% copper wire conductor inside Heavy-duty power adapter cord for RV or Marine. NEMA 5-15P to L5-30R 125V/3750W. Household regular 15A male 5-15 Plug. Shore Power twist lock 30 AMP female L5-30 receptacle with locking ring. Used 10 AWG copper inner wire, support max 30 Amp loading. Pins and terminals are made with nickel-plated brass to prevent oxidation rust.