Lock Washer Lock Washer Type Internal Tooth Lock Finish Plain Material Phosphor Bronze For Screw Size #4 Inside Diameter 0.123 in Outside Diameter 0.27 in Maximum Thickness 0.018 in Color Bronze Dimensional Standards ASME B18.21.1 For Use With Small Screw Heads Material Grade/Class Not Graded Pack Size Small Pack Rockwell Hardness B90 System of Measurement Inch Thickness Tolerance 0.012 in to 0.018 in Package Quantity 100