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 6220-01-443-3637
NSN 6685-00-678-5352
NSN 4140-01-300-7260
NSN 5935-00-550-1340
NSN 5935-00-911-3724
NSN 6220-01-261-6521
NSN 6150-01-433-2490
NSN 6105-01-470-4090
NSN 6685-01-154-8810
NSN 6320-00-242-3300
NSN 5990-00-678-6006
NSN 6130-01-054-3750