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 6650-01-462-5879
NSN 5965-01-210-7784
NSN 6650-01-023-5070
NSN 5990-00-804-0678
NSN 6130-00-855-2396
NSN 4140-01-369-0304
NSN 6240-00-263-0549
NSN 5945-01-574-4516
NSN 6130-01-170-6504
NSN 7035-01-429-7954
NSN 6135-00-782-6988
NSN 6150-01-268-6127