Yamaha combined the knowledge they learned in creating the Xeno tenor trombones with feedback from some of the world's great bass trombonists. The results speak for themselves;a state-of-the-art bass trombone with all specifications redesigned by an elite team of Yamaha designers and R&D experts. The 830 model includes features such as the newly designed yellow brass bell with a thinner wall for enhanced response, nickel silver slide crook for more substance to the sound, and a new rotor design which improves playability.Level Xeno Key of Bb/F/Gb/D Bore Large: .563" Bell Diameter 9 1/2" Shank Large Bell Material Yellow Brass Finish Clear Epoxy Lacquer Inner Slide Chrome-plated nickel silver, drawn Outer Slide Yellow Brass, drawn Mouthpiece 59L Rotors Two: in-line, independent, hand-lapped, mechanical linkage