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 5925-01-479-0213
NSN 5999-01-101-4372
NSN 5975-00-952-0890
NSN 6240-00-854-1962
NSN 6220-01-499-0635
NSN 5990-01-425-2175
NSN 5945-00-177-4676
NSN 5965-01-194-2785
NSN 4140-00-111-3166
NSN 5905-01-383-1364
NSN 5985-00-288-4864
NSN 5950-01-658-7013