The Kiev 88CM will fit Pentacon 6 lenses and Kiev 6c/60 lenses. It is a bayonet type mount, but the locking ring turns instead of the lens. (On the P6, not sure about the Kiev). The original Kiev 88 mount is sort of an interrupted screw that the lens makes about a quarter turn to lock. The Kiev 88 mount is similar to the old Hasselblad 1000F lens mount, but different enough to not be compatible.