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 6145-01-121-3560
NSN 6240-00-727-8573
NSN 2925-01-604-8984
NSN 5945-00-472-7823
NSN 5975-01-365-0127
NSN 5925-00-001-7446
NSN 6645-01-006-6735
NSN 5996-01-355-9583
NSN 5965-01-253-0451
NSN 6320-01-592-6248
NSN 5905-00-334-0212
NSN 6320-00-994-0179