John, You were right it is a Petri mount. 100% thanks. I was so dumb, you said it before but I was looking at a petri lens in my hand and it is m-42. That seems logical as m-42 almost became a universal mount for Pentax. Almost every lens maker offered a lens in M-42 so it seems. Well I really appreciate it. Now I can try to adapt it to my 4/3 mount. I always wonder what kid of image I am going to get when I try a new (to me) lens. Thanks again, AKf