I received this from a former member of the Japan Self-Defense Forces Band, but I'm selling it to declutter as I no longer use it. For large-bore euphoniums and trombones. For sale on other sites as well, so it's first-come, first-served. 【Product Description (May differ from modern versions)】 5GB D 25.50 MT. Quite a round rim. Same cup, throat, and backbore as a 5G, but with a round rim.