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 5998-01-377-4634
NSN 5990-01-288-7393
NSN 5998-00-753-1581
NSN 5950-01-418-0266
NSN 5965-01-106-1431
NSN 6650-00-150-6885
NSN 5975-00-324-2070
NSN 5998-01-168-6548
NSN 5930-01-406-3506
NSN 6645-01-409-0468
NSN 5990-01-532-6113
NSN 6320-01-551-3553