Perantucci PT-89 Tuba Mouthpiece, cup diameter: 32,0 mm, bowl-shaped, moderately deep, rim: 8,5 mm, rounded inner and other edges, Contact point in center, bore: 8,35 mm. Model PT-89 works well on medium-large and large-bore CC and Bb-Tubas, provides a good combination of easy and secure response and full, resonant tone.