5310-01-644-1013 (2.125ODX0.531IDX0.438 ALD4)
5310-01-644-1013 is equivalent to manufacture part number 2.125ODX0.531IDX0.438 AL. It is a bevel washer and is classified under Federal Supply Class 5310 (5310 - Nuts and Washers), stocked for defense, aerospace, MRO, and industrial maintenance applications. This item is cataloged in the NATO supply system under 5310 - Nuts and Washers and is available through NSN-PARTS for U.S. government MRO, and commercial procurement.