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 4140-00-602-5973
NSN 6105-00-244-1729
NSN 5998-00-461-3102
NSN 6130-01-634-0603
NSN 6150-00-537-5538
NSN 5975-00-305-8740
NSN 6130-00-051-0810
NSN 6620-01-569-4621
NSN 6105-01-456-8455
NSN 6135-00-100-0485
NSN 5945-00-617-8344
NSN 4140-01-623-4691