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 5999-01-394-4549
NSN 5975-01-191-5226
NSN 5996-01-160-5588
NSN 6240-01-611-1076
NSN 6145-01-378-4321
NSN 6320-01-420-0340
NSN 5990-01-040-6358
NSN 6150-01-010-2829
NSN 6685-00-267-9480
NSN 5895-00-066-8710
NSN 5935-00-188-8945
NSN 7035-01-659-3054