Just found this lens buried under a pile of broken camera accessories. Bought it at less than $10USD. I realised it was an enlarger lens and went to find out about it online. This lens is for UPA-510, a portable photographic enlarger, info from
http://www.krahe-sw.de/kamerasammlung/Kamera-Seiten/kamera_12_29_upa-510.htm I decided to clean it up and reverse mount the lens. It was done by embeded it into the M42 extension tube. I called it the 22/150 dual purpose lens. This is because by using a measuring tape, this lens reverse mounted can focus down to 150cm and rightly mounted can focus down to 22cm. It behaves similary to a projector which have center sharpness.
Reverse mounted
Rightly mounted
Embedded in the M42 extension tube