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 5985-01-444-1552
NSN 6320-00-004-9158
NSN 5895-00-086-3231
NSN 6240-00-364-0850
NSN 5996-01-337-6190
NSN 5935-01-108-4615
NSN 5960-00-809-9944
NSN 6110-00-280-2753
NSN 5935-01-599-5402
NSN 5835-01-262-5001
NSN 5998-00-599-1826
NSN 5930-01-271-5390