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 6220-01-613-5231
NSN 5996-00-103-2716
NSN 6240-01-435-5486
NSN 5990-00-454-6250
NSN 6110-00-706-8661
NSN 6145-01-455-3550
NSN 6110-01-362-9529
NSN 5998-01-579-5137
NSN 2925-01-587-3956
NSN 5975-01-381-2512
NSN 5910-01-033-5247
NSN 5855-01-246-4274