The size is 0.312 inches -26
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.
NSN 6105-01-205-1514
NSN 5910-01-290-3769
NSN 5895-00-292-2872
NSN 5920-01-501-5961
NSN 5895-01-630-5247
NSN 5999-00-869-2584
NSN 5999-01-177-9036
NSN 5998-01-071-2063
NSN 5835-01-244-8532
NSN 5975-01-055-0254
NSN 6620-00-900-3986
NSN 6610-01-062-9994