1-1/4" x 2.500" OD Thru-Hardened Plain Finish Steel SAE General Purpose Flat Washer / CROSS-SECTIONAL SHAPE STYLE: 1 RECTANGULAR HOLE DIAMETER: 1.368 INCHES MINIMUM AND 1.405 INCHES MAXIMUM PERIPHERAL SHAPE STYLE: 1 ROUND CENTER HOLE SHAPE STYLE: 1 ROUND THICKNESS: 0.136 INCHES MINIMUM AND 0.192 INCHES MAXIMUM OVERALL DIAMETER: 2.743 INCHES MINIMUM AND 2.780 INCHES MAXIMUM HARDNESS RATING: 38.0 ROCKWELL C MINIMUM AND 45.0 ROCKWELL C MAXIMUM PART NAME ASSIGNED BY CONTROLLING AGENCY: PLAIN FINISH SAE THRU-HARDENED FLAT WASHER MATERIAL: STEEL OVERALL SURFACE TREATMENT: OIL OVERALL