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 5910-01-514-0041
NSN 4140-01-373-1788
NSN 6130-01-528-7382
NSN 6135-01-167-7604
NSN 5920-01-138-6772
NSN 6685-01-304-4374
NSN 6150-01-166-1064
NSN 4140-01-315-7868
NSN 5950-01-141-9462
NSN 5905-01-163-7601
NSN 5930-01-207-1012
NSN 5960-00-545-8786