I know what air fittings are, I've never heard them called "C" fittings. Lincoln, Hansen-Milton or Industrial Interchange, Truflate, or Aero Speed.
I see that a couple of those are known by more than one code letter. If they can't be standardized as to a code, why try to do that at all?
"Above is an industrial style plug. They can be called by a few different names. For instance, this can be also be called a Milton plug, but more correctly it is Milton M-style. It is also known as type D or I/M style.
To make it even more confusing, Milton has a D-style plug, but that isn’t necessarily compatible with this style."
And even the one you pointed out.............
"Above is an automotive style plug: Also know as a Truflate, Type T, or C-style."
Why not just call it what it is.........A Truflate style coupler
We sold Aero and Truflate products back when they WERE, along with Lincoln which back then made all kinds of grease/ lube equipment.
