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 5930-01-552-8719
NSN 6645-01-442-6476
NSN 5930-00-231-3800
NSN 6135-01-449-2144
NSN 5950-00-062-5201
NSN 5999-01-315-7407
NSN 5910-01-419-5940
NSN 5960-01-243-0007
NSN 5930-01-339-9300
NSN 6110-01-027-1172
NSN 6150-01-604-8874
NSN 6135-01-540-2403