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 5996-01-217-3670
NSN 6610-01-014-3964
NSN 5945-00-633-7620
NSN 2925-00-215-4954
NSN 6110-01-595-4918
NSN 5915-01-348-2242
NSN 5990-01-309-3740
NSN 6110-01-555-8410
NSN 4140-00-813-1420
NSN 5996-01-057-1113
NSN 5996-01-463-3152
NSN 5965-01-560-8572