1/4" x 0.625" OD Thru-Hardened Plain Finish Steel SAE General Purpose Flat Washer / CROSS-SECTIONAL SHAPE STYLE: 1 RECTANGULAR HOLE DIAMETER: 0.281 INCHES NOMINAL PERIPHERAL SHAPE STYLE: 1 ROUND CENTER HOLE SHAPE STYLE: 1 ROUND THICKNESS: 0.075 INCHES NOMINAL OVERALL DIAMETER: 0.625 INCHES NOMINAL END ITEM IDENTIFICATION: MRAP - COMMON NSN - USED ON 2 MRAP VARIANTS AND 2 OTHER WEAPON SYSTEMS; MAXXPRO DASH ISS W/CROWS AND W/OGPK PART NAME ASSIGNED BY CONTROLLING AGENCY: WASHER,FLAT 1/4 (.281X.625X.07 SPECIAL FEATURES: 5/16 HARDENED WASHERS, .344 NOM ID,.688 NOM OD,.089 NOM THICKNESS.STEEL 1040 TO 1065 PER CEMS A-0,PART 1,QUENCHED AND TEMPERED TO RE36 TO 42. THESE WASHERS ARE INTENDED FOR USE IN HIGH CLAMPING LOADS, TO MINIMIZE EMBEDDING, AND TO AID TORQUING. MATERIAL: STEEL OVERALL MATERIAL DOCUMENT AND CLASSIFICATION: 1040 TO 1065 PER CEMS A-0, PART 1, QUENCHED AND TEMPERED TO RC 36 TO 42 MFR REF SINGLE MATERIAL RESPONSE OVERALL PROPRIETARY CHARACTERISTICS: NPAC SURFACE TREATMENT: ZINC OVERALL SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: ZINC TRIVALENT (ZN6A) CEMS G-20, CLASS 20, CLASS 6A MFR REF SINGLE TREATMENT RESPONSE OVERALL