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 6320-01-564-0893
NSN 6645-01-043-9587
NSN 5990-01-237-9044
NSN 6150-01-096-7616
NSN 6610-01-179-0116
NSN 5895-00-138-3009
NSN 5960-01-628-2760
NSN 6110-01-260-0032
NSN 6240-01-505-7424
NSN 5965-01-322-8136
NSN 5855-01-591-0466
NSN 5905-01-010-1806