The Bach 50AF3 inline independent double rotor bass trombone in the key of Bb/F/Gb features an 9-1/2" one-piece hand-hammered yellow brass bell that has defined the symphonic sound for generations. The .562" large bore combined with "Infinity" valves and open wrap F/Gb attachments offers outstanding clarity and projection with just less resistance. The chrome plated nickel silver inner handslide tubes provide the ideal surface for smooth and quick handslide action. The clear lacquer finish adds a subtle warmth to the sound overall. The Bach 50AF3 professional bass trombone is ideal for both symphonic and solo performance.