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 5950-01-646-1253
NSN 5915-01-030-1354
NSN 6105-00-753-7495
NSN 6645-00-279-1777
NSN 5920-00-168-4483
NSN 5920-00-925-2639
NSN 5925-01-589-8222
NSN 6130-01-158-6845
NSN 6320-01-371-3047
NSN 5910-01-251-9148
NSN 6150-00-244-2258
NSN 6650-01-141-1582