Split Lock Washer Lock Washer Type Split Lock Finish Zinc Plated Material Spring Steel For Screw Size 5/16 in Inside Diameter 0.322 in Outside Diameter 0.583 in Maximum Thickness 0.078 in Minimum Thickness 0.078 in Dimensional Standards ASME B18.21.1 Material Grade/Class Grade 2 Pack Size Small Pack Rockwell Hardness C38 System of Measurement Inch Thickness Tolerance 0.078 in to 0.125 in Package Quantity 100