This frame is legitimate De Rosa (Ugo and sons). I have seen at least two others. The decals do not correspond to the other ones that I have seen. I also don't recognize the little braze-on that appears just in front of the BB shell on the down tube. Perhaps an additional photo can be provided of this. The Columbus air tubeset came with a Columbus seatpost. If you don't have one of those seatposts a frameset like this is useless. Personally, I find the frame to be an unfortunate misstep on the part of Ugo and sons. They must have thought the same as they did not make many of these frames. I do however think that frames like this, as well as another questionable design, the De Rosa Tango, are important to show the path taken by the brand over the years.