Hillman Self-Piercing Sheeter Screws are metal roofing screws engineered to fasten thin pieces of metal to wood, fiberglass or metal primarily through a pre-drilled, or own generated hole in light gauge metal. Perfect for roofing construction, these sheet metal roofing screws feature a neoprene washer that provides a water-tight seal, and prevents corrosion between surfaces. These self-drilling sheet metal screws have a ceramic finish that exceeds the 1000 hour salt spray test, and are recommended for use for treated lumber. Self piercing screws penetrate metal and tap their own mating threads Steel-backed neoprene washer for water proofing Ceramic coat provides superior rust and corrosion protection Metal roofing screws recommended for use for treated woods Self-drilling sheet metal screws measure #10 diameter x 3" length Sheet metal roofing screws in gray hue to match metal sheeting No need to pre-drill hole in thin metal