The name Tenax was used by Goerz for a series of folding cameras, both plate and rollfilm, including a stereo model. When Goerz merged with ICA, Contessa-Nettel and Ernemann in 1926, the line was retired. Unsold stock may have been marked "Zeiss Ikon", this was a practice they used on many of the discontinued lines. No new stock was manufactured.
Although the engineers at Zeiss were very clever when it came to designing new products, they seemed to have trouble coming up with new names for these innovative products. In 1930 Zeiss introduced a new camera to take 24mm square photos on 35mm film. It was a very compact, and quick operating camera for its day. So they named it for the discontinued folding camera line.