Hex washer head self drilling screws are designed with a drill point at the tip to pre-drill the screw hole as you go with a “thrilling-like” action (threading or drilling) to eliminate separate drilling, tapping, and installation actions. The length of the drill determines the material thickness which the screw can reliably penetrate. They are ideal use for wood, metal or other tough materials and known for their effecient application performance and endurance. You could see them around because they are widely used in a variety of industries such as construction, manufacturing, engineering, assembling and so on; Screw Size: 10 ; Screw Length: 1/2"; High quality stainless steel 410; Package Included: 100 PCS ; 30-day money back guaranteed;