A Truss head screw has a head with flat underside and a slightly domed top. It has almost no exposed edge. Sheet Metal Screws have deep spiral threads the entire length and with a pointed end. Holds thin metal sheets together. Holds well in wood, Plastic, and Fiberglass. Manufactured from metal. Can be rotated into or out of the object using a screwdriver Perfect for fence building, this versatile fastener kit and screw set performs exceptionally well compared to standard wood screws or deck screws. Note: These screws are a distinct alternative to machine screws or self-drilling fasteners, providing optimal holding power when installed in pre-drilled holes.