Flat Washer, Dimensional Standards AMPG 2001 FL.06, Material Stainless Steel, Material Grade/Class 18-8, Finish Plain, For Screw Size 5/16 in, Inside Diameter 0.322 in, Outside Diameter 5/8 in, Maximum Thickness 3/32 in, System of Measurement Inch, Minimum Thickness 3/32 in, Inside Diameter Tolerance +/-0.010 in, Made in North America Made in North America, Material Quality Standards ASTM A582, Outside Diameter Tolerance +/-0.006 in