Plug into wall or car cigarette lighter if you have 2-pin connector as shown in 3rd pic.
Nameplate says 20X magnification. I think that is generous. I measure 16.5X. The film tray can accommodate fiche 4" wide by 5" deep. (Wider fiche will hang out of holder.)
1st picture shows blow-up of 110 negative.
Judging by the model number, this might be Visidyne's first commercial product. They went on to make bigger microfilm viewers.