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 6610-01-545-0766
NSN 5920-01-393-5460
NSN 6145-01-125-4106
NSN 5935-00-516-5251
NSN 6610-01-512-8154
NSN 6110-01-650-0183
NSN 6620-01-448-1423
NSN 5835-01-100-7405
NSN 5945-01-218-5645
NSN 6320-01-445-0325
NSN 5960-01-041-3048
NSN 5835-01-597-4820