Lock Washer, Bolt 1/4, 410 SS, PK100/ HOLE DIAMETER: 0.256 INCHES NOMINAL OUTSIDE DIAMETER: 0.478 INCHES NOMINAL EXTERNAL KEY QUANTITY: 12 MATERIAL THICKNESS: 0.022 INCHES MINIMUM AND 0.025 INCHES MAXIMUM END ITEM IDENTIFICATION: 6150-01-633-6567;LOAD BANK,ELECTRICAL PART NAME ASSIGNED BY CONTROLLING AGENCY: LOCK WASHER SPECIAL FEATURES: FITS BOLT SIZES: 0.250 INCH NOMINAL;ROCKWELL HARDNESS: C40 TO C50;MEETS/EXCEEDS: ASME B18.21.1 COLOR: SILVER OVERALL MATERIAL: STEEL COMP 410 OVERALL STYLE DESIGNATOR: 102 COUNTERSINK EXTERNAL TEETH