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 6610-01-189-3001
NSN 6620-01-235-3752
NSN 2925-00-147-8150
NSN 5945-01-050-7283
NSN 6650-01-145-5173
NSN 4140-01-058-6603
NSN 6610-01-431-7840
NSN 5950-00-615-9933
NSN 6645-01-215-9938
NSN 5920-01-519-8106
NSN 5996-00-316-5115
NSN 5855-01-229-3864