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 5996-01-252-4107
NSN 5990-00-538-7330
NSN 6105-01-231-0855
NSN 6105-01-141-6912
NSN 6145-01-215-0178
NSN 5915-01-099-6086
NSN 6240-01-260-3597
NSN 5920-01-052-6803
NSN 5999-00-761-3638
NSN 5996-00-428-8130
NSN 5905-00-087-9755
NSN 6150-01-513-7590