This is a beautiful and very high quality Hohner Atlantic IV Deluxe Accordion.

It is a 4 reed treble and 4 reed bass machine with the LMMH treble reed arrangement with very high quality, responsive, and stable reeds. It has a full size 19 1/8" keyboard. It also has a treble mute for further tone variations beyond the various reed combinations.

  I have rebuilt the treble and bass sections and replaced all the pads with new. I have replaced all the reed wax and all the leathers that needed replacement (about half). I tuned the accordion. It is set at A-440. I tuned the sharp middle of the treble section to 24 cents in the bottom end progressively to 14 cents at the top for a moderate to strong violin/ musette. All other reeds are tuned very dry.
  The Atlantic has an unusually deep bass section. The reeds go down to "E" below normal "C", or nearly an octave deeper than the normal. 

  The accordion plays beautifully and being at A-440 it will be in tune with other instruments if used in a band setting.
  The Atlantic model has the unusual construction of being made out of pressed and cast aluminum rather than the usual wood. As a result the accordion is much lighter than a normal accordion of comparable size and reed specification. This construction also means it is very strong and durable.
I have included some photos of the accordion as I was rebuilding it.