USSRPhoto Wiki Catalog
Smena 8 Stereo
This one has all the mechanics coupled, the focus and aperture rings are connected with beautifully crafted mechanisms.
The shutter release button had been relocated more towards the center and a single button serves as a release for both cameras with a makeshift bridge inside the camera. (see photos).
The creator had also been kind enough to provide both sizes of tripod mount sockets, but not so sure whether it was done on purpose... I am also not certain 100% whether the second camera is Smena 8 because of this difference.