ACDelco Professional Copper Core Spark Plugs ACDelco Professional Series Copper Core Conventional Spark Plugs are an economical choice for solid performance. Features and Benefits: Has a copper-core center electrode that helps provide improved heat transfer to the tip giving you the reliability you re looking for while improving its resistance to low-speed carbon fouling Precisely engineered and manufactured to provide everyday reliability and efficient performance The hot-tip insulator heats fast and fires hot The nickel-chrome alloy on the ground electrode and center electrode sheathing resists wear from spark erosion and the corrosive environment of the combustion chamber