Steel zinc. Has flattened head with a pierced hole. Lag screw thread. 1/4" x 3". 100-pieces per box. No. 372001: Material: Steel, Finish: Stainless Steel Zinc, Type: Lag Screw, Size: 1/4" x 3", Drive Style: Acoustical, Head Style: Flattened, Screw Length: 3", Screw Diameter: 1/4", Pkg Qty: 100, Package Type: Box