Countersunk Washer Material Grade/Class Not Graded Material Steel Finish Black Oxide For Screw Size 1/4 in Maximum Inside Diameter 0.281 in Outside Diameter 2 in Countersink Angle 82 Degrees Overall Height 0.281 in System of Measurement Inch Color Black For Use With Flat and Oval Head Screws Industry Standards AMPG 2002 FIN.31 Pack Size Small Pack Rockwell Hardness C40 Thickness Tolerance +/-0.010 in