The Courtois AC502B Mezzo Series Bass Trombone offers the player the flexible performance of an independent valve system combined with standard rotary valves. The AC502 Mezzo features a .562" bore design with a 9.5" two-piece bell design. The AC502B is a great choice for the player looking for a quality independent system bass trombone. The AC502B Mezzo includes a case and mouthpiece and is available in yellow or rose brass bell.