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 6145-01-350-8568
NSN 5998-00-067-3319
NSN 4140-01-471-3473
NSN 5915-01-515-0156
NSN 5895-01-261-9960
NSN 5975-01-117-1343
NSN 5835-01-200-8932
NSN 5895-00-247-3004
NSN 5905-00-257-9570
NSN 7035-00-585-2113
NSN 6220-01-528-0222
NSN 5855-01-642-7607