This is a normal shank Perantucci PT-66. I am selling it because I no longer use it. There are some signs of use and scratches, but there are no dents and it does not affect playing. It has a very strong resistance and I was able to play evenly from top to bottom. The mouthpiece feels sharp, so it may be a matter of preference. Quoted from the following site: Cup diameter: 32.5mm, hemispherical and medium depth. Rim width: 8.0mm Throat diameter: 8.0mm The PT-66 model is a traditional German-style mouthpiece that produces a clear and vibrant sound. It has a slightly deeper cup than the PT-64, so it produces a softer and louder sound. It is recommended to be used with F and E♭ tubas, but it can also be used with BB♭ and CC tubas, and it responds quickly and produces a clear, resonant sound.