Flat head self-tapping screw (countersunk head self-tapping screw) is a self-tapping fastener with tapered countersunk head. The head can sink flush into workpiece surface. It can cut its own thread when screwed into plastic, wood or thin metal sheet. Material: carbon steel; finishes: blue-white zinc plated, color zinc plated, black phosphated. Widely used in furniture, electrical equipment, sheet metal assembly.