Self-drilling screws are used in fastening materials to metal. Philips wafer head screws with wings are made to attached plywood or OSB to metal surfaces. The wings provide a clearance hold and break off when they hit the metal surface. The self-drilling point easily cuts through sheet metal and the coarse threads quickly grab and pull the screw into the mating material. The countersunk head is made to sink flush into a recessed hole. Made from zinc plated low carbon steel.