This is the early version of the Pilot.
I was visiting Scubapro factory in 1977, and I have seen one of these prototypes on the test bench.
The final version was a bit different.
The Pilot was not invented by Scubapro engineers, they did buy the design and the patent by an American inventor (I do not remember the name).
But here you can read the whole history:
Scubapro’s Pilot Regulator, how it came to be. There is a rumor that the Scubapro Pilot Regulator was created by a MIT student for a class project. NOT TRUE. I invented the Scubapro Pilot (US P
vintagescuba.proboards.com
Scubapro engineers did love the principle, but not how it was executed in the Pilot.
So they re-engineered it in what became the AIR-1, with parts fully compatible with the Pilot casing.
So most Pilots were retrofitted with Air-1 parts, which made it more reliable and easier to service and to tune.