Split Drive Anchors are available in boxes of 100 pieces. These tamper resistant concrete fasteners are made of a high strength, heat-treated carbon steel with zinc plating. Split Drive Anchors are all one piece with no nuts or washers needed. Split Drive Anchors are 1/4" in diameter and are available with a flat countersunk, or round head. Designed for light duty fastening in solid concrete, only a hammer is required for installation.