The Bach model 39 Eb alto trombone features a 6-1/2" one-piece hand-hammered bell designed for excellent resonance and projection. The .468" medium bore handslide design provides balanced and agile response. The clear lacquer finish provides a subtle warmth to the overall sound. The Bach Stradivarius model 39 alto trombone is designed for the player looking for a high-performance alto trombone.