You open the tube and show it empty. You can even place a few silk handkerchiefs in it. They vanish and in their place two 3D dice appear on top of each other (see images) The dice are 3.5 inches square. You can easily handle them, throw them in the air etc.
Nice illusion. It is no longer on the market.
This is a great trick for the right kind of act. A total mini-illusion you will really enjoy performing.