These Grade 410 Stainless Steel Flat Head Self-Drilling Screws feature a notched tip for drilling holes in metal and fastening in a single operation. They eliminate the need for a pilot bit or a pre-drilled hole and are easily installed with a Screwgun. These screws feature a Flat Countersunk Head with a Phillips Drive for a flush appearance when fastening wood or composite materials to metal. Manufactured from 410 Series Martensitic Stainless Steel which has a higher hardness than 18-8 Stainless Steel but is less corrosion resistant than 18-8 and will be magnetic. Length is measured from the top of the head. See the Technical Specs section below for the Cut Depth (Metal Thickness) drilling capacity of a self-drilling screw.