Thank you for viewing. This is a Vincent Bach mouthpiece that responds well from high to low notes and has a rich sound. I used it with a YAMAHA euphonium 321S. This mouthpiece is a "deep period" type, believed to have been manufactured between 1970 and 1980. Specifications: 4 Cup Depth: M Cup Inner Diameter: 26.00mm Rim: MW Used item, for small shank The shank tip is slightly deformed, but it did not affect the performance. Thank you.