M20 x 37mm OD DIN 125 Grade HV200 Yellow Zinc Finish Steel Type A General Purpose Flat Washer / CROSS-SECTIONAL SHAPE STYLE: 1 RECTANGULAR HOLE DIAMETER: 21.0 MILLIMETERS NOMINAL PERIPHERAL SHAPE STYLE: 1 ROUND CENTER HOLE SHAPE STYLE: 1 ROUND THICKNESS: 3.0 MILLIMETERS NOMINAL OVERALL DIAMETER: 37.0 MILLIMETERS NOMINAL END ITEM IDENTIFICATION: CHILLER SET, 85 TON, HALIFAX CLASS SHIP HARDNESS RATING: 91.5 ROCKWELL B NOMINAL MATERIAL: STEEL OVERALL SURFACE TREATMENT: CHROMATE ZINC OVERALL