Slotted Washer Color Black Finish Black Oxide Flat Washer Type Slotted Flat Washer For Screw Size 3/8 in Material Steel Material Grade/Class Grade 5 Maximum Thickness 0.375 in Minimum Thickness 0.375 in Outside Diameter 2 in Pack Size Small Pack Rockwell Hardness C40 Surface Slot Width 0.406 in System of Measurement Inch Thickness Tolerance +/-0.015 in