This is an Adams 4/4 C Prototype Tuba, tested and used in Metropolitan Opera of New York City. It is in raw brass, featuring a Gold brass, 17 3/4" bell and nickel lead pipe. It shows signs of use, as well as solder spots where braces were moved around during the testing stages. From the Adams website: The geometry of the Adams C tuba ensures an extremely powerful and dark tone with plenty of core. When testing and adjusting the C tuba, we focused on crafting an instrument with great projection and a rich overtone spectrum that would sound impressive in any large concert hall.