Flat Head Phillips Drive Ply-Metal Winged Self-Drilling Wood to Metal Screw. Features Wings on screw tip for clearing of wood prior to reaching metal allowing screw to pass through wood layer and fully engage in the metal layer below. Wings will break away upon contact with metal, allowing the self-drilling screw tip to drill and tap into the metal for a tight well fastened connection of the wood and metal layers together. Flat head design countersinks into surface and fits flush with the wood. The exterior grade Grey Spex finish provides excellent corrosion resistance.