The Canadian Brass MB-83 has the same exterior shell as the Arnold Jacobs Heritage Tuba Mouthpiece but has a smaller diameter. This design emphasizes the presence of the fundamental in the sound and really locks in the upper register. The MB-83 has a deep funnel shaped cup with a very large throat that creates a dark, resonant sound.
Inner diameter: 32mm/1.26in
Cup: Long V-shaped funnel
Rim: Narrow with moderate roundness, clearly defined inner edge