The Vistarama and the Hama compact have their original boxes. The Super Hanorama uses natural diffused light to view slides- no batteries required. The Vistarama requires 4 C size batteries and the Hama Compact takes 2 penlight batteries. The Museum of Design in Plastics in the UK has a Vistarama as part of its exhibition.
The view sliders can be used to view slides, of course, but I think they look great –on display. Those funky 60s blues and greens! and the funky 60s typefont. Lovely.