British Gypsum Drywall Screws are phosphate-coated for corrosion resistance, and have self-tapping points to help you reliably and securely fix plasterboard linings. Plasterboard linings must be fixed securely to achieve optimum fire and acoustic performance. These drywall screws let you fix 12.5mm or 15mm single layer plasterboard linings to maximum 0.8mm gauge metal or timber frames.