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 5905-00-225-0607
NSN 4140-00-567-9291
NSN 5935-01-535-3682
NSN 6130-01-202-8025
NSN 6220-01-168-9383
NSN 6105-00-226-0884
NSN 6320-01-449-1014
NSN 5935-01-399-4102
NSN 5915-00-283-1664
NSN 6685-01-531-1910
NSN 5910-00-758-3031
NSN 5915-00-141-0410