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 6685-01-610-5258
NSN 6610-01-487-4626
NSN 6320-01-383-3257
NSN 6320-01-407-8663
NSN 6650-00-877-6499
NSN 6610-01-305-8863
NSN 6135-01-167-7604
NSN 5975-01-348-8938
NSN 5895-01-012-7085
NSN 6130-01-431-6734
NSN 6130-01-358-1457
NSN 5910-00-373-3743