Made for the Contax, you will have to experiment to successfully use their parallax markings on your Leica. Russian Kiev 28-135 Finder . Post war, black, a copy of the Zeiss Contax finder. I was surprised to see that despite the so so finish, the optics give a great image. Just rotate the mounting to the desired focal length.
Parallax compensation is also combined in the rotating frameline mount.
Finder These were sold with the Komura 2x Teleconverter for Leica Screw mount lenses in the 1980's. It's a nice zoom finder, if you can find one. There was also a 80-270 Komura finder which is rather mediocre. I'm told of excellent quality, German made. This was the classic second 'spectacle' eye seen in the famous Andreas Feininger portrait of the Leica photographer.