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 6220-01-409-1585
NSN 5975-01-108-3947
NSN 5935-00-227-5823
NSN 5925-00-834-0272
NSN 5996-00-133-7748
NSN 6240-01-194-1602
NSN 6620-00-257-2783
NSN 5950-00-389-3760
NSN 6320-01-111-8851
NSN 6105-01-296-7048
NSN 5935-01-203-1174
NSN 5895-01-513-5927