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 5950-01-203-8047
NSN 5895-00-915-9057
NSN 6105-00-171-6521
NSN 6620-01-199-8580
NSN 5935-00-189-9364
NSN 6650-01-003-9355
NSN 5999-01-558-7248
NSN 5920-01-510-6355
NSN 5950-00-880-6140
NSN 6650-00-900-0049
NSN 6650-01-364-1313
NSN 4140-00-106-6780