This is one of the many Carl Zeiss standard lenses available with the M42 screw mount. It is one of the later, more modern designs and features multi-coated elements.
I have never actually tested this lens myself, but I would assume that it offers excellent optical performance.
The minimum focusing distance of only 0.35 meter is also worth metioning and quitre unique among standard lenses.
For more information on the large variety of standard lenses available from Carl Zeiss Jena please follow this link.