This is a Stork trombone mouthpiece. The bore diameter is only about 1cm, so it's not a large shank. (I'm not sure of the details, so please let me know what measurements you'd like.) It's a size similar to a Bach 12c. It doesn't feel as small as the rim diameter listed on the HP. It responds very well and is easy to play from low notes to high Bb and beyond. Stork mouthpieces are great, aren't they? This is a used item, so there are minor scratches and blackening. I think it's at a typical used condition level, but there may be areas that are difficult to see in the photos or that reflect light. Please be sure to ask any questions you have before purchasing. If you are concerned about differences in feel or other minor details, please purchase a new item. It will be simply packaged.