Adams TBA1 Alto TromboneThe TBA1 Eb Bb alto trombone features an open wrap and 0. 480" nickel silver single bore hand slide design that makes the instrument respond with ease. This TBA1 features a 7" red brass bell for great projection and a superb resonance. Handcrafted in Adams production facilities, this state of the art alto trombone combines a direct, rich, and sparkling sound with superior technical qualities and slide positions that feel like a tenor trombone. Key: Eb