Yamaha Trumpet Mouthpiece in size 11C4 is comparable to a Bach Trumpet Mouthpiece in size 7C.  This quality brass mouthpiece contributes to the high regard Yamaha has earned among beginner and professional musicians alike. The result of a special approach to design and manufacturing, Yamaha mouthpieces deliver the performance and comfort required where they are needed most: where instrument meets musician. The mouthpiece production technique used by Yamaha ensures consistent quality mouthpieces, time after time.  Other manufacturers use a specific cutting tool to create every mouthpiece, which causes problems as tools start to wear. This can result in inconsistent quality and poor performance. Yamahas computer-aided design system and computer controlled lathe work together to produce the most precise, consistent mouthpieces in the world.