Bach Tuba / Sousaphone Mouthpiece Features:

• Model No. / Depth of Cup / Depth of Cup / Approx. Cup Dia. / Rim Shape / Description
  
  7 / Deep / Medium / 33.25 mm / Medium wide. / A large mouthpiece with full, lively tone and a splendid low register, for players with a strong embouchure. Recommended for large-bore instruments.
• 12 / Deep / Medium / 32.75 mm / Medium wide. / Fairly large diameter, producing a big, vivid tone.
• 18 / Deep / Medium / 32.10 mm / Medium wide. / Our best-selling mouthpiece for all-around work. Has an even high register, substantial tone of excellent carrying power.
• 22 / Deep / Medium / 31.60 mm / Medium wide. / Slightly smaller than No. 18. Recommended for use in school bands.
• 24W / Deep / Medium / 31.25 mm / Wide, well rounded. / A versatile mouthpiece with lively tone, suitable for school bands.
• 24AW / Deep / Deep / 31.25 mm / Wide, well rounded. / An excellent mouthpiece whenever a sonorous, dark tone quality
• of enormous volume is desirable.
• 25 / Deep / Medium / 30.60 mm / Medium wide. / A fairly small mouthpiece suitable for young students.
• 30E / Deep / Medium shallow / 30.00 mm / Medium wide. / A small mouthpiece requiring little volume of air. For the young student with a small mouth.
• 32E / Deep / Medium shallow / 29.50 mm / Medium wide. / A small mouthpiece for the lightweight bass horn, or for the less robust player seeking a robust tone.
  
  With the exception of the junior mouthpieces, Nos. 30E and 32E, Bach tuba mouthpieces can be used equally well on BB-flat and E-flat tuba. There is no good reason for making mouthpieces for E-flat tuba any smaller or shallower, because a player using an E tuba actually transposes a fourth and uses the instrument in the lower register, for which a larger-sized mouthpiece is to be given preference. Nos. 7, 18, 24W and 24AW have larger backbores.