Back-tracked to the manufacturer? This is a very old lens design/name. It look brand new so are they still making them? I had one of these, let's see, about 50 years ago. It was polished alloy and it was to fit onto an Exakta 11b I owned at the time. I cannot remember much about it except there was precious little in the way of contrast and the lens barrel had quite a 'wobble' where it joins at the focusing section. (It was quite old) 100mm will make it a superb portrait lens. I would love to see what the results are like.