Split Lock Washer, Lock Washer Type Split Lock, Finish Black Oxide, Material Steel, For Screw Size #10, Inside Diameter 0.193 in, Outside Diameter 0.294 in, Maximum Thickness 0.047 in, Minimum Thickness 0.047 in, Dimensional Standards ASME B18.21.1, Material Grade/Class Not Graded, Pack Size Small Pack, Rockwell Hardness C40 to C50, Package Quantity 100 High Collar Split Lock Washers are generally thicker than regular Split Lock Washers, with a smaller O.D. that allows them to fit into a counterbored hole and to be used with screws, such as socket-head cap screws, that have small-diameter heads. The high collar also provides additional vibration resistance.