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 6240-01-058-1777
NSN 5835-00-170-5238
NSN 7035-00-064-7008
NSN 5999-01-480-3705
NSN 5975-00-901-3180
NSN 6150-01-109-2266
NSN 5950-00-216-9212
NSN 5895-00-758-2151
NSN 5998-01-648-3533
NSN 5950-00-042-6541
NSN 5990-00-756-6059
NSN 5950-00-378-9959