These Forgefix Pozidriv Self-Tapping Screws are made from A2 stainless steel, which will not corrode, rust or stain with ordinary water like other steel does. Their Pan Head, with a flat under head surface makes the screw ideal to lay flat on sheet material of all types, thus reducing deformation. The screws tap their own thread in a pre-drilled pilot hole, in sheet metal. The screws are single threaded to resist pull-out. APPLICATION Ideal for use in many DIY, ironmongery, engineering, electrical and plumbing applications.