Iouseki stones and Binchotan charcoal, when used with the Water Pitcher (sold separately), create filtered, mineral-rich water. The stones come from the mountains in Kanazawa, the capital city of Ishikawa Prefecture, on the Sea of Japan coast. The charcoal is specially prepared for potable water use, and also works as a deodorizer to create odor-free water. In place of filters that need monthly replacement and add to landfill, Iouseki stones and Binchotan charcoal last up to six months (depending on use).