I have found this on ebay. The same tool you are thinking of buying for a hell of lot less money. What I do not like is other stuff at his shop looks like rubbish
He means that rotates relative to the spindle. If you pay attention in your picture you see the upper die support being a bit tilted one side, that is because it's free to move, as it couldn't be otherwise. It's pointless to push sellers for much technical data, they are sellers not watchmakers.
Once again I suggest that you go for the other type, the price in the 1st link you included is robbery and the design is, after all, outdated.