The C1-1 S5 has the same rim size and contour as our C1-1 S1, but with a shallower cup. It is a great orchestral mouthpiece for people who like a large diameter, round rim, and who prefer a cup that is between a conventional B and C cup.  The sound is a bit brighter than the C1-1 S1, but it is still a big mouthpiece!  It’s popular with 1B and 1C players who relate well to the very rounded 1-1 rim contour but want better intonation, an easier upper register and more consistent feel in all registers.