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 5895-00-186-3441
NSN 6685-00-455-3729
NSN 5855-01-369-5037
NSN 6220-01-170-6913
NSN 6130-01-130-9415
NSN 5950-01-528-7143
NSN 5960-01-046-8308
NSN 7035-01-371-0091
NSN 6130-00-833-7763
NSN 5895-01-456-0066
NSN 7035-01-411-6062
NSN 5895-00-280-7528