Steel Flat Washer, Hot-Dipped Galvanized Finish, ASTM F436 Type 1, 1/2" Screw Size, 17/32" ID, 1-1/16" OD, 0.135" Thick (Pack of 50) Flat washer provides a bearing surface for fastener load distribution or acts as a spacer Steel is often used in applications where strength is the primary consideration Hot-dipped galvanized finish offers excellent corrosion resistance Meets ASTM F436 Type 1 specifications