Quality brass mouthpieces contribute to the high regard Yamaha has earned among beginning and professional musicians alike. The result of a special approach to design and manufacture, Yamaha mouthpieces deliver the performance and comfort required where they are needed most: where instrument meets musician. Inner Diameter: 16.88 Contour: semi-flat Thickness: standard Cup Depth: standard Throat: 3.65 Backbore: semi-narrow Playing Charateristics: Rim designed for outstanding facility and flexibili