The Berkey Black BB9-2 Water replacement Filters are designed for the Berkey Water System, including models like the Berkey Light, Imperial Berkey, and Big Berkey. These filters are made of plastic and feature a 2-stage filtration method with carbon/charcoal for effective removal of bacteria. With a compact design at 2 inches in depth and 2 inches in width, these filters are suitable for household use and come in a pack of 2. Proudly made in the United States by the trusted brand Berkey, these water filters ensure clean and safe drinking water for you and your family.