Not all yixing pots were used for tea brewing, or at least that’s the way it seems sometimes. In things like senchado sometimes they were used for water cooling/pouring rather than tea making. It’s not always clear to me why one is designated as water dropper rather than teapot. When there’s a pair sometimes one gets assigned one job and the other the job of tea making. In any case, this pot is called “zini suichu” which literally means purple clay water dropper. 145ml.