Carl Zeiss Jenna 35mm f2.8 Biometar-Red-T Contax Mount, see pictures. One of 1500 made according to Google. This made circa 1950. Glass very nice. Fit Contax I, II, III, IIa, IIIa. Lens focus smooth and aperture operates fine. Tight fit to speed group selector on Contax I not a defect but just way it was made. However due to 70 years old sell parts or repair. Understand very rare lens. Ask questions before buy as no returns. Will post pictures taken with it when available. [CONTAX I and IIa cameras pictured are not part of sale but suggested use only.] Sale offer only for 35mm Biometar lens.