Interesting old Russian glass - fast with bokeh. M42 / EF adapter supplied.

"The lens has, what is referred to as optical vignetting, meaning that out of focus “bokeh-balls” becomes more elipsoid as you move away from the center of the image. Also referred to, as “Cat-eye” effect, this phenomenon gives a pronounced feeling that the background “swirls” around the center focus subject."  Read full review.