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 5996-01-556-4277
NSN 5910-00-559-1138
NSN 6150-01-588-9883
NSN 5915-00-605-7560
NSN 5935-01-569-7454
NSN 5910-00-264-3584
NSN 5925-00-839-4689
NSN 5950-00-020-6790
NSN 5835-00-851-6470
NSN 5905-00-937-2065
NSN 7035-01-480-9761
NSN 5960-01-226-7297