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 6685-01-577-3715
NSN 5925-01-337-3336
NSN 5895-01-302-5819
NSN 5855-01-658-1044
NSN 5910-00-879-2904
NSN 5945-01-194-9592
NSN 5920-01-151-9117
NSN 5999-01-557-2968
NSN 6150-01-144-5176
NSN 5945-01-430-4328
NSN 5996-00-073-2659
NSN 7035-01-353-6861