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 6220-00-528-7752
NSN 5895-01-372-6561
NSN 6645-01-202-7986
NSN 5935-01-289-9586
NSN 6240-00-717-0844
NSN 5965-01-368-2966
NSN 5996-00-646-3833
NSN 5999-01-009-1689
NSN 5855-01-654-8603
NSN 5920-00-701-1200
NSN 6645-00-392-8728
NSN 5835-00-918-8169