Universal turret viewfinder for 28, 35, 50, 85, 135mm lenses

Such viewfinder is used to frame picture when non-standard lens mounted onto your rangefinder camera.

It has a turret with 5 positions - 28mm, 35mm, 50mm, 85m and 135mm lens.

If used from accessory shoe of a camera, it can help to estimate parallax affection for close shots as well.