Special o-ring material, per mil-p-5510c, do not dupe to any other nsn
An adapter having machine threads (straight threads other than pipe or hose series) designed to accommodate a tube on one end or an unthreaded end designed to accommodate a tube. The other end has external or internal machine threads (straight threads other than pipe or hose series) and is designed to facilitate a gasket, preformed packing, washer, or the like to form a seal at the boss. It is designed to join a tube or tube fitting to a boss or boss fitting in a straight line on items such as tanks, housings, valve fittings, and the like. See also coupling, tube and nipple, tube.
Classification: Other fittings nesoi of iron or nonalloy steel
NSN 5996-00-681-0490
NSN 4140-01-634-0330
NSN 5915-00-080-6385
NSN 6110-01-014-3840
NSN 6610-01-293-4705
NSN 6135-01-439-8669
NSN 5920-01-425-7268
NSN 5960-00-629-7044
NSN 5915-00-469-3492
NSN 6220-00-534-1829
NSN 5999-01-163-3816
NSN 5925-01-352-3349