A nut, flat on top and bottom, having 4 flat sides. 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 4140-00-739-2033
NSN 6685-00-559-2742
NSN 6320-00-790-4844
NSN 5910-01-475-5478
NSN 5985-01-379-4701
NSN 4140-01-634-0330
NSN 7035-01-442-7947
NSN 5835-01-564-3486
NSN 5895-01-415-5710
NSN 4140-01-363-2258
NSN 6320-01-449-1014
NSN 6135-00-840-6451