I thought the aperture numbers a little strange, given the specs have the minimum at f/4. Pic of actual item, shows the marking starting below 4. Makes sense if this is not actual aperture numbers, but 'position' numbers for lack of a better term, which would be converted to the real aperture setting. Wide open (=f/4) then half of that, etc...
The current owner used it on his Beseler enlarger with good effect. Looks like it has an additional adapter plate in place. I have the Componon-S in 80mm, so this is really just curiosity to see if it would bring any other added capability to my line up. Ideally, I'll find a set of APO versions of the lenses, but I'm not willing to spend any real money to get them, patiently waiting for a great deal to come along...