This is a 120 piece set of self-drilling screws from Amtech. The screws feature a hexagonal head and are made from zinc-plated hardened carbon steel. They are housed in a convenient plastic storage case. These screws are ideal for securing corrugated metal or PVC roofing panels, cladding, trunking, and other sheet metal assembly parts. No pre-drilling or tapping of threads is required; simply use a corded or cordless drill with the correct size socket for installation.