Wow, I looked at the images from the link, Giovannimusica, and they certainly look very cool. The slides and much of the tubing are exactly the same as that of the French Horn, or at least very similar. (I play the Horn, I should know). Anyways, very interesting; it looks a lot like a Horn with an elongated bell. I have seen Wagner Tubas in a live performance of Bruckner 8, but never up close before. Thanks for the link.