A headless fastener externally threaded on both ends with each threaded portion of one but not necessarily the same nominal diameter. It is designed to be locked in place by either a ring, lock, serrated or a ring, lock, keyed.
NSN 6685-00-296-0392
NSN 6620-01-350-5103
NSN 5920-01-254-5152
NSN 5920-01-592-4873
NSN 4140-00-991-0766
NSN 4140-00-904-8153
NSN 5855-01-225-5855
NSN 5915-01-271-3028
NSN 4140-00-289-9263
NSN 2925-00-087-2465
NSN 5925-00-246-4645
NSN 6620-01-025-1443