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 6110-01-218-9472
NSN 5960-01-275-5896
NSN 6130-00-408-5055
NSN 2925-00-542-8285
NSN 6645-01-258-3229
NSN 5930-01-492-6590
NSN 6650-00-231-7843
NSN 5835-01-488-6678
NSN 5975-00-381-3850
NSN 6105-01-431-8998
NSN 6645-01-578-7959
NSN 5895-01-413-8682