SAE Washer Flat Washer Type SAE Dimensional Standards ASME B18.22.1 Type A Narrow SAE Standard Material Steel Material Grade/Class Grade 8 Finish Zinc Yellow For Screw Size 5/16 in Inside Diameter 0.344 in Outside Diameter 11/16 in Maximum Thickness 0.065 in System of Measurement Inch Minimum Thickness 0.065 in Color Yellow Material Quality Standards ASTM F436 Pack Size Small Pack Rockwell Hardness 38HRC Thickness Tolerance +0.015/-0.014 in Package Quantity 50