Get this Fastenmaster TimberLok Coarse Steel Hex Head Heavy-Duty Wood Screws for delivery. No predrilling. Faster and easier than 3/8 in. lag screw. Countersinking head style. Guaranteed corrosion resistance – ACQ approved. IBC/IRC code compliant – ICC-ES ESR-1078. Unique tapered head countersinks easily into wood. Includes a 5/16 in. hex driver bit.