Welfast Fasteners specializes in Pin Type Anchors also known as Hit Anchors for push through applications. Hit Anchors are impact expansion type concrete anchors with an interior hole extending the length of the anchor. A hardened drive pin comes along the assembly inserted in the bolt. The anchor is threaded on the upper portion where the drive pin is inserted. Other end of the anchor has four equally spaced slots for a portion of its length, with ribs extending the circumference of the anchor for a portion of its length.