Made of quality brass the 37C4 alto horn mouthpieces is highly regarded among beginning and professional musicians alike. The result of a special approach to design and manufacture the 37C4 alto horn mouthpieces delivers the performance and comfort required where they are needed most: where instrument meets musician. The mouthpiece production techniques used by Yamaha promises consistent quality time after time. Our computer-aided design system and computer controlled lathe work together to produce the most precise consistent mouthpieces in the world. The 37C4 alto horn mouthpiece has a medium inner rim diameter and cup volume which produces a bright tone outstanding endurance and easy of play from the lowest to highest notes