Asme b 18.2.2
A nut, flat on top and bottom having 6 flat sides. For items which have internal tapered or straight (parallel) pipe threads, specific electrical conduit size designation, and which when installed, provide a method of tightening to lock the connection, see locknut, electrical conduit. See also locknut, tube fitting. For items having a thickness (or height) exceeding two times the width across the flats, use post, electrical-mechanical equipment. (when height or thickness and/or width across the flats is designated as a tolerance dimension, the maximum dimension will be used to determine compliance.)
NSN 5975-01-614-4088
NSN 5905-01-645-5023
NSN 5835-01-493-1826
NSN 6130-01-138-9055
NSN 5945-01-202-8119
NSN 6135-01-482-3989
NSN 6105-01-166-4923
NSN 6620-00-286-5721
NSN 6135-00-823-3034
NSN 5835-01-013-9321
NSN 4140-00-007-5726
NSN 6645-00-467-6094