Unoscop

 Here's a good solid slide projector made in Sweden from the late forties by the Fritz Meist company. 

Fritz Meist had come to Sweden in the late thirties from Germany as a refugee and started a small import-export business mostly concerned with photography equipment, expanding into a small factory after the war. The company soon was struggling and the manager Einar Bohmelin was given the job of saving it. He designed various bits of photographic equipment for the company to manufacture including the Unibox camera and this slide projector which became standard equipment in Swedish schools up into the seventies.

History in Swedish here.