Updated: I checked the lens again and added more photos, please take a close look into it. It is usable, can be better if doing a CLA'ed service.
Original listing:
Carl Zeiss Jena Biotar 58mm f2 lens brass black paint Red T coating Exakta mount. Lots of aperture blades, I counted about 17x if no mis-counted.
This is the most sought after version of this Carl Zeiss Jena Biotar lens. Made in late 1940's, with brass lens body black paint. Kind of rare to find compared to later aluminum version. Thus has been a sought after item since vintage time. Simply there are not many of them around.
Excellent cosmetics, some partial haze, may still be usable. If buyer plans to use it for paid work then get it CLA serviced by all means. If just try it out, then just shoot as is and spend money later.
Vintage Zeiss and Leica used whale's oil for lubrication thus all vintage lenses have encountered haze problem regardless of storage condition.