This Ukrainian made SKF-1 beam splitter is unusual in as much as it is a camera attachment that then converts into a stereo viewer, achieved by inserting the stereo lenses into the lens attachment.
The Beam Splitter takes two images through one lens onto a single 35mm frame (measuring 36mm x 24mm). The lens attachment requires a camera with a focal length of 58mm and so is ideally suited to Zenit (Zenith) cameras. The lens must also have either a 49mm or 52mm filter thread to screw the attachment onto.
The SKF-1 was initially produced in 1985 and was manufactured for at least six years, maybe longer.
This is a great beamsplitter set to play around with. The quality of the parts is very good and several people have succeeded in using the beamsplitter on a digital camera.
Also read the excellent article below by Luiz Paracampo.