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 5999-00-754-5188
NSN 5895-01-559-2202
NSN 5996-01-242-9710
NSN 6130-01-368-2123
NSN 4140-00-069-5154
NSN 5905-01-101-6186
NSN 6240-00-777-1878
NSN 6135-01-579-3534
NSN 6320-01-050-1290
NSN 5905-01-252-9015
NSN 6130-00-411-4323
NSN 6110-00-628-5128