The C1-2 S3 has a flatter rim contour than our other 1 series mouthpieces, and a fairly sharp bite on the inner edge.  This mouthpiece has the same rim as the C1-2D S3 but with a slightly shallower cup and is a popular mouthpiece for classical and orchestral playing.  Players who like the feel of the old Bach 1 size, but would like a slightly shallower cup, usually love the C1-2 S3 rim.  1C players who prefer more bite on the inner rim also love this size.