1/4" Mechanical Zinc Finish Heavy Split Lock Washer / HOLE DIAMETER: 0.260 INCHES NOMINAL OUTSIDE DIAMETER: 0.489 INCHES NOMINAL MATERIAL THICKNESS: 0.077 INCHES NOMINAL END ITEM IDENTIFICATION: MASTIFF 2; MRAP - COUGAR CAT1A1 ISS, CAT2A1 ISS, CAT1A1 AND CAT2A1 SEAT SURVIVABILITY PART NAME ASSIGNED BY CONTROLLING AGENCY: 1/4" ZINC FINISH HEAVY SPLIT LOCK WASHER MATERIAL: STEEL OVERALL SURFACE TREATMENT: ZINC OVERALL STYLE DESIGNATOR: 108 SPLIT HELICAL-RIGHT HAND