Scubapro is usually good about cross compatibility across years for a given model but when the 620 came out I wondered what the changed other than the titanium barrel, this is a new model that has very subtle size variations vs the s600, they do look very similar
The 620 does measure slightly smaller across the face
About 1mm but the cover is shaped slightly different
The 620 cover is a little thicker and has the shapes that flow from the cover to the body
The threads differ very slightly so the cover can’t interchange
The diaphragms do look interchangeable so that and the same poppet seat orifice should keep the old 600 going for years to come
The big change is the square on the air barrel, otherwise people (like me) would be swapping Ti barrels in place of the plastic, here is the old style the square is square to the case...
The 620 is turned 45°, very clever.
The 620 does measure slightly smaller across the face
About 1mm but the cover is shaped slightly different
The 620 cover is a little thicker and has the shapes that flow from the cover to the body
The threads differ very slightly so the cover can’t interchange
The diaphragms do look interchangeable so that and the same poppet seat orifice should keep the old 600 going for years to come
The big change is the square on the air barrel, otherwise people (like me) would be swapping Ti barrels in place of the plastic, here is the old style the square is square to the case...
The 620 is turned 45°, very clever.