Visor stereoscopic ZEISS IKON O with lighting fixture slide 5 x 5 cm, which have been taken from the stereo accessories Steritar A, B and D, as they use the Contaflex I and II, the Contaflex III and IV and Contina III . Lighting fixture works with a battery or a transformer. Made around 1955 by Zeiss Ikon AG. Stuttgart. Weird. A detailed description can be found in PHOTOGRAPHY AND RESEARCH, Volume 7, (internal memoranda Ikon Zeiss AG). For more information, see the instruction manual. Measures Viewer / Glass 5x5