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 5925-01-591-2408
NSN 5905-00-539-5746
NSN 6610-01-531-6980
NSN 6130-00-472-2500
NSN 5835-01-488-6678
NSN 5975-01-378-7355
NSN 5985-01-214-8979
NSN 5985-01-408-0779
NSN 5920-01-463-0791
NSN 5905-01-201-7202
NSN 5905-00-928-9056
NSN 5950-00-250-8738