A 3D filming lens, very sharp as well for a normal lens.  Pentax PK mount. Please find the details in the following web page. 

Please refer to the pentaxforum review and description to learn more about the lens. It is rare!!!

The aperture ring is loose and shaky, and the PKA function doesn't work . There are some slight mist alike thing on the glass near the rear group. I used the lens as is. 

Please refer to the pictures for cosmetic condition. 

Comes with front and back cap. Filters on the lens are not included for the sale. 

All lenses are well documented. Please feel free to ask any questions.