Van eredeti Pentax,

https://www.ebay.com/itm/Genuine-Asahi-Pentax-PK-M42-Screw-Adapter-Mount-Adapter-K-30120-Pristine/312833604407?hash=item48d655fb37:g:rSIAAOSwDMtdweQk

és olcsó kínai adapter.

https://www.ebay.com/itm/M42-PK-M42-for-Pentax-PK-K-Mount-Adapter-Ring-Focus-Infinity-Manual-Focus-M42-PK/333167906272?hash=item4d925acde0:g:w3oAAOSwInJcvt5L