Hillman #12 - 14 x 1-1/2 In. Washer Head Self-Drilling Sheet Metal Screw (100 Ct.)Self drilling screws are manufactured for use in wood, fiberglass and metal. They possess a drill point which enables the screw to drill its own hole in thin gauge steel; no pre drilled holes are necessary. The sharp threads create their own mating thread when drilled into the material, and provide a stronger grip to your surface. Perfect for roofing construction, these screws have a neoprene washer that provides a water tight seal, and prevents