This blue label Voit Lung is one of the most rare of the Voits.  I have found no evidence that it was ever cataloged and the numbers made is unknown.  The internals of this regulator are identical to the US Divers Mistral.  This one is one of the best examples I have ever seen.  The satin chrome on the can normally did not fair well on these early Voit regulators, but this one cleaned up rather well.  I was so excited to dive this beauty that I took it straight to the quarry once rebuilt and dived it with my sheet rubber Hydroglove and USD triples.  The 40 degree water seemed warmer with a blue label voit Lung.