The Truss Head Philips Sheet Metal Screw in 18-8/304 Stainless Steel with TYPE "A" Thread is used in Sheet Metal, Fiberglass, Wood and many other applications. This screws feature a lower profile, larger diameter head. These have become a favorite choice in the marine industry for everything from rub rails and radio boxes to trim and insulation in engine rooms. Made of 18-8/304 Stainless Steel, these are the choice to use where Corrosion Resistance is a primary job of the fastener.