Schilke MOST 4 Trumpet, Mouthpiece for trumpet, Signature Series, Inner cup diameter: 16.94 mm, 25 backbore, Silver-plated, Full and clear sound with excellent evenness over the whole range and in every dynamic range, Equipped with a standard cup depth and the MOST-B2 signature backbore, The mouthpiece rim was developed especially for Osamu Takahashi and Toshio Tanaka and lies in terms of contour and grip between rim shape #3 and the semi-flat rim shape #4, The smallest cup inside diameter of all MOST mouthpieces, With a semi-flat cup and the MOST-B2 Signature Backbore