The Bach 50B3LO inline independent double rotor bass trombone in the key of Bb/F/Gb features an 10-1/2″ 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.