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 6320-01-228-2380
NSN 5835-00-833-7080
NSN 5945-01-216-9655
NSN 5945-01-483-7232
NSN 5855-01-658-4510
NSN 5996-01-349-6986
NSN 5998-00-905-6772
NSN 5990-01-044-4767
NSN 6150-01-361-1041
NSN 6110-00-642-1120
NSN 5905-01-030-1741
NSN 2925-00-054-3550