The bright line or mirror finder for 3,5cm lenses first appears in 1950 in the Leitz/Leica accessory lists. Initially with the focal length specification 3,5cm engraved this was changed during the production period to 35mm. There have been different engraving styles on the top of the SBLOO viewfinder and there was also a very hard to find black paint SBLOO version.
The bright line finders were still in the assortment up to the 1970s, whereby the versions for the wide angle lenses 21mm and 28mm are produced in modified form to the present day.
For collectors, bright line finders are a very popular field of activity due to their many small details changes, and many are looking for viewfinders matching with an already owned lens to complement the historically correct accessories.
In the condition offered here the SBLOO is very difficult to find nowadays, and the offered 3,5cm viewfinder is a nice addition to an Elmar 3.5cm or Summaron 3,5cm lens and e.g. Leica screw mount camera, such as the Leica IIIf or M-series models like an Leica M3 .
Total production: not known
Rarity forecast: R5