A quality wide angle with outstanding build and smooth operation, even after 50 years. A vintage lens that will out perform many more modern contempories.  This example has been very well cared for. Optically and cosmetically A. You can buy this lens for your M42 screw mount Pentax or choose the option of adding a K&F precision M42-E adapter which enables this lens to be mounted on Sony E-mount, focus peaking cameras. Both lens caps supplied.