The Wedge 4WB screw rim is designed to be used with the wedge backbore (shank). The mouthpiece has the double oval cup. (DOC) which provides the added efficiency of a smaller mouthpiece with a big sound, clear attacks and flexibility of the larger mouthpiece.
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.
Standard Brand DOC (Double Oval Cup) mouthpieces have an accentuated oval shape which extends right to the base of the cup.
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 orbicularis is muscle between the mouthpiece and the natural outward curvature of the teeth at those points.