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 5998-00-477-0865
NSN 5998-01-390-1003
NSN 2925-01-243-0328
NSN 6620-01-426-2220
NSN 5945-01-494-3560
NSN 6685-01-296-0746
NSN 2925-01-351-9748
NSN 6240-00-846-9815
NSN 5895-01-414-8704
NSN 6135-00-900-2139
NSN 6110-01-338-6746
NSN 5990-01-633-9503