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 6135-01-124-2376
NSN 7035-01-056-5350
NSN 5999-01-439-0869
NSN 6645-00-914-2820
NSN 5920-01-283-1093
NSN 5990-01-527-7640
NSN 6650-01-589-1892
NSN 5910-01-605-3393
NSN 5915-01-064-2113
NSN 5950-00-433-8914
NSN 5835-01-502-9228
NSN 6320-01-246-4390