Most people are of the filter bottle is called filtering barrel, which also does not hold water, in my opinion, is to install water is called barrel, but do not think so. It is also a product, they thought was filled with filtered water of the filter, which can also put these things is called a filter barrel, if our billing words into a filter barrel to billing, the first time do not know will be a fan of such a small mistake, and filter bottle in three level are all equipped with filter, the first level device net carbon, second stage particle carbon, third installed network carbon, are known as the core, to waste water filtering water, the most used is 10 inches outside buckle transparent bottles, American also used the most, because European American, and 10 inch internal buckle white bottle, transparent bottles, 20 inches is the big blue bottle, big blue bottle generally installed in commercial water purifier, filter bottle 10 inches are transparent and white bottle mainly, there are other colors, but rarely, like 20 inch blue bottle cap is black