The Bach 50B3O 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 the 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 50B3O professional bass trombone is ideal for both symphonic and solo performance.