Ramset Powder Fastening Systems 1524SDP 3-inch Washered Pin are drive pins with washers to increase bearing surface against the material to be fastened. Ramset powder actuated fasteners are specifically fabricated to meet the exacting requirements of toughness and durability that enable them to penetrate dense concrete and structural quality steel. The metal washer is 16 gauge. A square washer indicates 3-inch pin has been installed. It comes 100 per box. Shank diameter = .145 Head diameter = .300