A spring-wound mechanism inside the instrument moves a paper roll over tubes connected to the accordion's 44 notes. A foot pump bellows connected via a hose to the accordion provides the air needed to for the instrument to sound its notes.
It's bit like a player-piano/organ strapped to your chest. I had no idea such things existed. Amazing. This one comes with 7 different programmed paper rolls.
Here is the eBay listing with more photographs of the automatic accordion called the Hohner Magic Organa