Hex Head Large Diameter Screw Bolt Anchor for Concrete is a high-strength anchor with hardened self-tapping threads that offer a unique undercutting design for anchoring into concrete, masonry and CMU Block. Available in diameters from 1/4” up to 3/4”, these strong but easy to use masonry anchors require no secondary setting process during installation. The one-piece Hex Head with integrated washer features locking serrations on the washer face for a secure vibration resistant grip when installed. Easily installed by hand using a socket wrench or with an Impact Wrench. Large diameter concrete screw anchors are removable and reusable. Manufactured of heat-treated carbon steel, these screw anchors also feature a heavy duty exterior grade mechanically-galvanized finish for excellent corrosion resistance in exterior or interior applications.