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 5915-01-468-9123
NSN 5975-01-096-6270
NSN 5930-01-116-2944
NSN 5920-00-989-7254
NSN 6650-01-146-5000
NSN 6130-01-278-6948
NSN 6145-00-840-6685
NSN 6685-01-567-5073
NSN 5910-01-508-5027
NSN 5975-01-512-0172
NSN 6150-00-719-6119
NSN 6620-01-329-7510