Extra Thick USS Washer, Flat Washer Type USS, 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 3/16 in, System of Measurement Inch, Minimum Thickness 11/64 in, Color Yellow, Material Quality Standards ASTM A325, ASTM A490, ASTM F436, Pack Size Small Pack, Resistance Properties Corrosion-Resistant, Rockwell Hardness C38, Package Quantity 50