Chart of the different sizes Model :12 Depth of cup : Medium Diameter : 32.75 mm Rim Shape : Medium wide Fairly large diameter, producing a big, vivid tone. Model :18 Depth of Cup :Medium Diameter : 32.10 mm Rim Shape : Medium wide Our best-selling mouthpiece for all-around work. Has an even high register, substantial tone of excellent carrying power. Model :22 Depth of Cup :Medium Diameter : 31.60 mm Rim Shape :Medium wide Slightly smaller than No. 18. Recommended for use in school bands. Model : 24W Depth of Cup :Medium Diameter :31.25 mm Rim Shape : Wide A versatile mouthpiece with lively tone, suitable for school bands.Model :24AW Depth of Cup :Deep Diameter : 31.25 mm Rim Shape : Wide An excellent mouthpiece whenever a sonorous, dark tone quality well rounded. Can produce an enormous volume if desired. Model : 25 Depth of Cup : Medium Diameter : 30.60 mm Rim Shape : Medium wide A fairly small mouthpiece suitable for young students. Model : 30E Depth of Cup : Medium Diameter : 30.00 mm Rim Shape :Medium wide A small mouthpiece requiring little volume of air. Shallow for a very young student. Model : 32E Depth of Cup : Medium Diameter : 29.50 mm Rim Shape : Medium wide A small mouthpiece for the lightweight bass horn, or for the less shallow 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 BBb and Eb tuba. There is no good reason for making mouthpieces for Eb tuba any smaller or shallower, because a player using an Eb 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.
