Description: Optional. Vendor:acdelco. Vendor #R43XLS. Black Onyx coating helps reduce corrosion Copper core provides great heat transfer and helps maximize plug durability In 03212019_LegalReviewCatalogingStatements Nickel-chrome alloy sheathing helps prevent corrosion on center electrode Available for use in Marine applications This GM Genuine part is designed, engineered and tested to rigorous standards, and are backed by General Motors