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 6320-01-084-7523
NSN 5990-00-013-6862
NSN 5975-01-634-0678
NSN 6110-01-474-8181
NSN 5998-01-281-0634
NSN 5990-01-340-3575
NSN 5835-00-792-8438
NSN 5998-01-345-9718
NSN 5985-00-170-6768
NSN 5990-01-421-5342
NSN 5975-01-624-2816
NSN 5895-01-583-0383