Casmen window operator

Hello! You have a very old style operator that is unfortunately not made anymore. It's very similar to our 39-028E and 39-027E, but the bearing at the end of the arm is the big difference: ours are round and thick compared to yours, which is skinny and square. 

You may still be able to get our 39-028E and 39-027E to work, but it would require changing the track to our 39-505. The issue is that this mounts to the face of the sash and I don't believe that's how it works on yours. That may indeed render these parts incompatible without a lot of retrofitting. You may want the help of a local professional to do that work for you. Even if it would be possible I would imagine it would take a lot of trial and error to get right.