Slotted Washer Finish Plain Flat Washer Type Slotted Flat Washer For Screw Size 5/16 in Material Stainless Steel Material Grade/Class 18-8 Maximum Thickness 0.313 in Minimum Thickness 0.313 in Outside Diameter 1 1/4 in Pack Size Small Pack Rockwell Hardness B83 to B95 Slot Width 0.344 in System of Measurement Inch Thickness Tolerance +/-0.010 in