4-40 x 3/16 Phillips Flat 82 Undercut Machine Screw Black Zinc Plated (10,000) . Black Zinc is an acidic, low temperature powdered product developed to impart a black conversion coating of zinc die casting, galvanized stock and electroplated zinc parts. The black coating serves as a base for organic coatings (lacquers, paints, waxes and oils) and also provides an esthetic appeal.
