This is the "SIGRO Ⅰ" trombone/euphonium large shank mouthpiece from the Japanese mouthpiece maker "willie's." Inner Diameter: 26.70mm Throat Diameter: 7.10mm Cup Depth: 3G This is the signature model of Daniel Morandini, principal trombonist at La Scala Opera House in Milan, after having been principal trombonist with the Israel Philharmonic and the New York Philharmonic. This is the model he used when he played a Shires trombone, and I myself also used it with a Shires. Although the rim size is large, the cup isn't that deep (it's listed as 3G, but I don't think it's that deep), and I think you can get a good sound from top to bottom. There are some scratches from use, but it's relatively clean. Feel free to ask any questions!