Small inside diameter, like a Bach 15. Shallow "V" style cup and a bore of .250"
Very free-blowing for a small mouthpiece.
#2, ID like Bach 12.
#3, ID like Bach 11
The Rosolino piece has proven very popular but there were a few players who could not function with the small diameter of the original. I made several with larger inside diameters and the guys loved them. These are called the Rosolino #2 (12C diameter ) and the Rosolino #3 (11C diameter)