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 6130-00-065-4849
NSN 5910-01-333-3865
NSN 6220-01-498-7211
NSN 5895-01-609-2945
NSN 6620-00-064-3598
NSN 5855-01-436-7621
NSN 7035-01-026-1171
NSN 6220-00-302-9462
NSN 6685-00-432-3576
NSN 6130-01-142-4522
NSN 5910-01-378-9150
NSN 5998-01-530-4634