The RT-45 tuba mouthpiece by Robert Tucci is an excellent complement to a large CC or BBb tuba. The combination of the RT-45's 32.5mm inner diameter, medium cup depth, and large bore allows the tuba to do the "heavy lifting" for you. This is a great mouthpiece for the tubist that wants to support a large ensemble with a large tuba but doesn't need a care for the size of the the RT-48 or RT-50.
Inner Diameter: 32.5mm/1.28in
Rim: 7.6mm/.3in, narrow