The Novoflex PENTLEI Lens Mount Adapter is the required adapter ring to connect a Pentax K type camera body to the Novoflex Balpro series bellows system. This adapter ring has the Leica M39 screw mount at the other end, but you will still need the Novoflex #APRO (B&H #NOA35) to go from this PENTLEI ring to the bellows itself.
Note:
Although the lens will fit physically, access to various lens and camera functions are not guaranteed. No electronic communication is possible between the camera and the lens.