Spax Pan Head Screws - Patented Multi-head design featuring ribs on the underside of the head for a clean, flush penetration into wood, sheet metal, masonry and plastics. These are coarse thread screws, made of carbon steel, available in a silver zinc finish. Thread serrations reduce the torque required to fully drive these screws. For use with either a Phillips or Square Drive bit. Self drilling/self tapping. Spax has discontinued making this size. Sale limited to supply on hand. Engineered in Germany....made in USA.