Lock Washer Lock Washer Type Internal Tooth Lock Finish Zinc Plated Material Steel For Screw Size 1/4 in Inside Diameter 0.267 in Outside Diameter 0.478 in Maximum Thickness 0.028 in Color Clear Dimensional Standards ASNI B18.22.1 For Use With Machine Screws Material Grade/Class Not Graded Pack Size Small Pack Rockwell Hardness C40 to C50 System of Measurement Inch Thickness Tolerance -0.005 in Package Quantity 100