USS Washer, Flat Washer Type USS, Dimensional Standards ASME B18.22.1, Material Steel, Material Grade/Class Grade 8, Finish Zinc Yellow, For Screw Size 1/2 in, Inside Diameter 0.563 in, Outside Diameter 1 3/8 in, Maximum Thickness 0.051 in, System of Measurement Inch, Minimum Thickness 0.08 in, Color Yellow, Material Quality Standards ASTM F436, Pack Size Small Pack, Rockwell Hardness RC38, Package Quantity 25