USS Washer, Flat Washer Type USS, Dimensional Standards ASME B18.22.1 Type A Wide, USS Standard, Material Steel, Material Grade/Class Grade 2, Finish Zinc Plated, For Screw Size 1/2 in, Inside Diameter 0.563 in, Outside Diameter 1 3/8 in, Maximum Thickness 0.132 in, System of Measurement Inch, Minimum Thickness 0.086 in, Pack Size Bulk Pack, Resistance Properties , Rockwell Hardness 38HRC, Thickness Tolerance +/-0.025 in, Package Quantity 1300