Bach 33524AW Tuba & Sousaphone Mouthpiece, 24AW Deep cup depth 31.25 mm cup diameter Wide, well-rounded rim Great for dark tones Enormous volume 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. Our best-selling mouthpiece for all-around work. Has an even high register 12 / Deep / Medium / 32.75 mm / Medium wide. / Fairly large diameter, producing a big, vivid tone. 18 / Deep / Medium / 32.10 mm Recommended for large-bore instruments.