The rim size of the B4S S2 is based on a Mt. Vernon 3C owned by our friend Lew Soloff.  It is a slightly larger diameter than a “modern” 3C, with a more rounded inner rim contour.  This size is very popular for classical, jazz, and all-around playing, and players who like the 2C or 1 1/2C rim diameters usually love the B4S S2.  It is also very popular with 3C players who would like a slightly larger mouthpiece and a bigger sound without giving up and range or endurance.