ELCO TapFast: 12-24 x 2-3/4 Drilit Wood-to-Metal Self Drilling ScrewsFor efficient fastening of wood or composite materials to steel These self drilling fasteners eliminate separate drilling and tapping operations for faster installation in wood to metal applications. Specifications Description 12 24 x 2 3 4 Diameter #12 Length 2 3 4 in. Material Carbon Steel Head Size #12 Diameter, #3 Philips Wafer Head Screw Type Drilit Self Drill Screws for Wood to Metal Applications Point Type #4 w WIngs Typical Wood Thickness 1 5