Description
These mouthpieces use a logical numbering system. First number: the diameter of the cup. The small numbers are too narrow, the largest numbers are too big for all but a few players. The first letter is the cup depth A-E (shallow to deepest), second number is the contour of the rim (4, has a bit more surface contacting the lips. The second letter is for the back bore (A-tight, E-most open).