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 5990-00-956-9130
NSN 5985-01-526-0321
NSN 6135-01-426-4962
NSN 5996-00-007-9845
NSN 5925-00-431-3256
NSN 4140-01-551-3589
NSN 5905-00-543-2144
NSN 6220-01-567-2426
NSN 5998-00-401-4484
NSN 6645-01-234-5555
NSN 5990-00-444-6987
NSN 6105-01-106-4649