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 5905-01-089-3831
NSN 6685-01-623-7694
NSN 5925-01-272-9577
NSN 6645-01-589-0983
NSN 5920-00-825-2572
NSN 5925-00-031-4108
NSN 6650-00-932-2048
NSN 6130-01-159-3697
NSN 5950-00-691-3098
NSN 5930-01-392-1787
NSN 5965-01-347-1670
NSN 6145-00-866-8994