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 5998-01-003-3031
NSN 6145-00-255-1480
NSN 7035-01-296-4737
NSN 6610-01-035-1252
NSN 5960-00-262-2905
NSN 5930-01-235-9508
NSN 6220-00-262-7863
NSN 5925-00-139-4829
NSN 4140-01-648-9450
NSN 6110-01-374-3196
NSN 2925-00-215-4954
NSN 6135-01-443-7716