Originally posted by stevebrot Back to the tele/wide finders. I have one similar to that pictured in the OP that I use on my FSU rangefinder cameras. The wide works well for 35mm lens on 35mm film and the tele is about the same as a 85mm. So, figure about the same as a 24mm and 55mm on the K-01.
That corresponds with what I have seen. For the tele-wide finders (that is, a single finder with two sets of guide lines in the view, as opposed to a finder dedicated to one lens or a "universal" type, with multiple optics), there seem to be three main types available
Tele-Wide Japan - black, three chrome bands, yellow reflective coating on optic. Available with Yashica and Lentar conversion lens pairs, probably others. Looks like a LOT of these were made.
Kaligar - brushed aluminum body (although I think I've seen one in black), orange reflective coating on optic. Available with both square and rectangular guides in the finder, depending on which camera it was intended for.
Petri - flared shape to black body. Only rectangular guides (I think), since it was intended for Petri cameras. It seems like a lot of the Petri lens kits available are missing their finder - either left on the camera or already scavenged for other use.