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 5930-01-457-3805
NSN 5996-01-391-9585
NSN 6650-00-090-2944
NSN 6110-01-067-3741
NSN 5895-01-497-7326
NSN 5996-01-060-4642
NSN 6150-01-517-3318
NSN 6685-01-190-3374
NSN 5835-00-315-3797
NSN 6135-00-793-1809
NSN 5935-01-100-0448
NSN 7035-01-502-9703