HILLMAN 1/4 in. D X 1-3/4 in. L Steel Round Head Strike Anchor 50 pcStrike Anchors are designed for concrete applications only. For installation, anchor is inserted into pilot hole, nail is struck and expands the anchor, locking it in place. These anchors are removable with a claw hammer. * UPC: 008236109412 Manufacturer Part No: 375650 Diameter: 1 4 in. Length: 1 3 4 in. Material: Steel Product Type: Strike Anchor Head Style: Round Head Required Drill Hole Size: 1 4 in. Screw Length: 1 3 4 in. Minimum Embedment: 1 1