Heavy-duty 100% copper wire conductor inside. Molded plug and connector, more safe than assembly type. NEMA 14-30 250V molding 4-prong male plug, NEMA 6-50 250V molding female receptacle. Molded with electroplated copper terminal in order to avoid surface oxidation effectively. Used 10 AWG*3 stranded copper inner wire, support max 30 Amp loading. Length: 18 inches (1.5 feet). Color: Black