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 6320-01-441-2438
NSN 6105-01-177-6092
NSN 6610-00-801-4652
NSN 5895-01-640-7311
NSN 6105-01-648-8053
NSN 5965-01-459-8203
NSN 6110-01-532-4044
NSN 5996-01-027-0702
NSN 4140-01-493-9653
NSN 5925-01-189-4083
NSN 5950-00-840-8335
NSN 6110-00-669-6586