What you have is half of the Healthways SCUBAIR-J regulator. It was made from the early through mid 1960s (I believe that the 62-63 editions had the chrome exhaust tees, later models had rubber tees) Not the easiest breathing regulators but they are nearly indestructible. I have a complete one, but it is not working all that well and parts are hard to find.
Oops, guess it's not a SCUBAIR-J. Now that I've seen the diagram, what the hell were they thinking??!!
Too DAAM Many double hoses, It's not a hobby, it's an addiction.