Large shank mouthpiece. The standard mouthpiece for Bach 42 series trombones. This is the most popular size for large bore trombones in general and is often copied by other makers. For most players it gives an appropriate full sound and even response in all registers; even intonation, especially in the upper registers; a relatively dark sound at high dynamic levels; and a clear articulation overall. • 25.50mm diameter rim. • Deep cup. • 429 backbore. • 0.276" throat. • Medium-wide, semi-flat rim. • Silver plated