The tip rail contributes to the brightness or darkness of tone; a thinner, narrower tip allows for higher partials -- thus more brightness.

The facing is actually comprised of two curves -- the two side rails -- one on each side of the mouthpiece, so that it is important that these be symmetrical. Each brand of mouthpiece has a number or letter that designates the facing, referring primarily to the tip opening, i.e. the distance between the reed and mouthpiece at the very tip.  A larger number indicates a greater opening, but the designations do not usually indicate the length of the facing.

The baffle is the area inside the mouthpiece that is directly beneath the reed. The distance from the reed to the baffle is critical in determining brightness and darkness of tone. Generally, a higher baffle, i.e. closer to the reed, produces a brighter tone.

The walls normally come straight down from the top of the side rails to the baffle. Early saxophone mouthpieces had concave sidewalls. By contrast, the walls descend diagonally from the side rails on the E. Rousseau JMA and E. Rousseau JMT mouthpieces.

The window is the opening between the side rails that is covered by the reed.

The reed rests on the table to provide a good seal between the reed and mouthpiece; the table must be kept clean and smooth. E. Rousseau hard rubber mouthpieces are designed to have a very slight concave area in the center of the table to ensure a secure fit for the reed. The arch is located between the table at the end of the window, and can be easily seen by looking through the mouthpiece from rounded end to tip.

* The chamber is a combination of the shapes of the baffle, walls and arch.