Leitz folding viewfinder for 90mm lenses. Product code SEROO. It was introduced in 1935 together with folding finders for 73mm and 135mm lenses.
Life-size (1×) magnification. Chrome finish. A black finish version also exists, but it is extremely rare.
Parallax correction is marked in meters. When folded, it is only 12mm thick, allowing the camera to remain compact even with the finder attached.
There are very slight signs of wear on the shoe mount and the base, but otherwise the chrome plating is beautiful, and the finder is overall in very clean condition.
The glass is clear and crisp, with no cleaning marks or traces of fungus.
It comes with the original box and is also well suited for a collection.