RBT Brand Stereo Slide Viewer
Not to be left out, RBT (Rauumbildtechnik GmbH), the German company which has plastic slide mounts produced for them, had the popular, affordable, cardboard slide viewer, produced for them too, imprinted with their name.
Stereo slides, American or European format, slip easily into rear pocket of this grab light viewer. Focusing is accomplished by squeezing top and bottom of viewer edges, yet viewer folds almost completely flat for convenient mailing or publication inclusion.
RBT branding is printed on outside face of viewer. Remainder of viewer is blank for any personal branding or stickers.