While this is not a "SCUBA" unit it is very high in the coolness factor.  It is intended to be used with surface supplied air.  The diver is attached to the surface via a low pressure hose and the single stage regulator provides air to the diver for presumably a very long working dive.  This unit is currently missing the mouthpiece and hoses, but is in almost new condition and appears to have been used very little.  Take a look at the really old school diaphragm that appears to still be dive worthy after all these years.