Pre-war Tenax I
By the late 1920's, the Leica had given the 35mm format respect. Zeiss realized that the small image size could be used to create a very compact, but quick shooting camera, capable of making high quality pictures. And this they did.
The Tenax used a lever next to the lens to wind the film and cock the shutter, like the more sophisticated Tenax II. The lens was a 35/3.5 Novar mounted in a Compur shutter. It had a folding optical finder, which helped keep it small, yet made it easy to view through.
It was listed under catalog number 570/27, and was offered until 1941. Is fairly uncommon now, it must not have enjoyed much commercial success.
In 1948, the East German Zeiss put the camera back into production. They offered it with a coated 37.5/3.5 Tessar, first in Compur shutter, later with unmarked Tempor.