Kodak Service Range Finder designed for various '40s and '50s Kodaks - Kodak 35, Monitor, etc. 5/8" diameter x .085" (15.9 x 2.2mm) clip disc may not fit modern cold/hot shoes. Of course, it can be used hand-held.
This one is in very good condition. Smooth adjuster wheel and bright image, but with a bit of dust visible.
Both split image and distance scale are seen in the viewfinder. However, due to some mirror desilvering, the split image is partially obscured. Certainly suitable as a display item or prop.