Black Drywall Screws: Coarse ThreadHardened carbon steel screws with an extremely corrosion resistant phosphate finish. Self-starting needle point and twin threads for fast fixing of dry lining and plasterboard to timber framing and studs without the need for pre-drilling. Bugle head sets the screw to the correct depth without tearing the plasterboard lining paper. The length of screw selected for any specific thickness of board should be sufficient to give 25mm penetration into the timber framing. No.2 Phillips head.