3/8 inch
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 5965-01-399-8454
NSN 5835-00-146-9928
NSN 6620-01-183-1900
NSN 6650-00-098-6128
NSN 5930-01-394-4964
NSN 6240-00-369-9768
NSN 5950-00-296-5505
NSN 5920-00-468-3074
NSN 6150-01-225-8075
NSN 5950-01-534-9833
NSN 5960-01-442-7950
NSN 6685-01-655-6321