The item is a flight safety critical aircraft part (fscap).
A nut having 6 flat sides and an integral washer which extends beyond the flats or periphery. An integral feature is incorporated for locking on the threads of a mating member.
Classification: Nuts of iron or steel
NSN 5855-01-526-0131
NSN 5998-00-999-8700
NSN 5855-01-074-3335
NSN 6130-01-642-5339
NSN 5999-01-608-2248
NSN 5855-00-055-1694
NSN 5998-01-250-4057
NSN 5950-01-512-1465
NSN 6105-01-160-7719
NSN 5930-00-554-1064
NSN 5990-00-197-0159
NSN 5925-00-186-8669