This is a Perantucci 4☆D4, used by many professional musicians. The inner rim diameter feels like a Bach 7-10. It's somewhat shallow, feeling like a middle ground between a Bob Reeves 41-42S. It's very easy to control, and the dynamics have a high degree of freedom. I think it's a very well-designed mouthpiece. It has a design with excellent response. It has a moderate resistance and is easy to play high notes. It's a vintage item, so it shows signs of use, but there are no scratches or damage that would interfere with playing.