The CobraTork heavy duty concrete screw anchor features a raised head for better grip, a notched thread making it easier to cut through the concrete, and cavities designed to collect the debris. Also, the anchor can be easily removed if required. Suitable for all masonry material the one-piece anchor has a finished hex head locking washer mechanism. The chamfered tip makes for easy installation and the screw is heat-treated with corrosion resistant Cobracoat. This pack contains 40 1/2" x 3" hex head concrete screws.