Simpson Strong Tie THD50612H 1/2-Inch by 6-1/2-Inch Titen HD Zinc Plated Heavy Duty Screw Anchor for Concrete/Masonry, 20 per Pack Easy post-installation inspection head stamped with anchor length in inches Specialized head treated process creates superior hardness Tested per AC193 to ensure outstanding performance in both cracked and uncracked concrete Threads along the length of the anchor undercut the concrete and efficiently transfer the load to the base material Designed to install using standard ANSI tolerance drill bits