Heavy brass Dräger 'Taucherautomat' Model D 6000. Developed in the early 1940's as a safety device for divers. Once the flow is set it will be the same at any depth.
This unit was serviced recently and is technically ok. These are still being used by hobby hard hat divers but do know that this early version of the Taucherautomat is officially no longer allowed for professional use, this because when you (accidentally) close the air flow wheel then it is closed. The newer version of the Taucherautomaat (T11801) cannot be entirely closed: also when the adjustment wheel is put to 0 there still will an airflow pass on which a diver can survive.
Price: €300,- plus shipping
(The newer version of this device, the T11801, we also have these in stock but not yet advertized)
Draeger D 6000 Taucherautomat