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 7035-01-562-7857
NSN 5975-00-865-3537
NSN 5998-00-381-9597
NSN 5985-01-474-5141
NSN 5905-01-145-4552
NSN 6105-01-546-2330
NSN 6320-01-465-2028
NSN 6620-01-515-5378
NSN 6620-01-279-0651
NSN 6650-01-203-8263
NSN 5985-01-565-0844
NSN 5960-01-015-8655