Boltmasters Ribbed Countersunk Metal Tek Class 3 Screws allowing for easy self embeddment and a flush finish. These screws are designed for a faster install, whilst the self drilling tip eliminates the need for pre-drilling. Often used for fixing cement sheeting or villa board to steel framing. These screws have a hardened steel self drilling point (tek point) which cuts through mild steel without the need for pre-drilling. Also ideal for fixing panelling to steel frame sections.