The Wedge 1.5C screw rim is designed to be used with the wedge backbore (shank). The cup is based on a shallow version of a Bach 1.5C.
The Wedge mouthpiece differs from a traditional mouthpiece in several subtle but important ways.The parts of the rim touching the middle of the upper and lower lip (at 12 o'clock and 6 o'clock) are the same width as a conventional rim, or slightly wider.
The parts of the rim touching the corners of the embouchure (at 3 o'clock and 9 'clock) slope away from the centre of the mouthpiece. This shifts the high point of the lateral rim toward the inside, and makes the sides narrower than the upper and lower parts of the rim. The combination of rim contours produces a slightly oval shape in the rim.
The sides of the rim are curved away from the embouchure, slightly reducing pressure there. This has the important effect of improving circulation and decreasing trauma to the embouchure from 2 o'clock to 4 o'clock and 8 o'clock to 10 o'clock where the rim tends to impinge the orbicular is muscle between the mouthpiece and the natural outward curvature of the teeth at those points.