A tube coupling nut with the shank end accommodating a smaller tube size than is accommodated by the tube fitting which connects to the threaded end.
NSN 6130-01-254-8784
NSN 6110-01-239-4180
NSN 5930-01-624-5485
NSN 5975-00-518-4977
NSN 5996-00-301-5243
NSN 6110-00-082-0268
NSN 6220-00-754-3452
NSN 6135-01-437-7741
NSN 6240-00-404-6183
NSN 2925-01-139-5144
NSN 5935-01-217-0910
NSN 6240-01-107-9795