The Berkey Water Filter System with Black Berkey and Fluoride Filters takes water filtration to a new level! The Black Berkey filters are some of the most efficient filters available on the market and remove a long list of contaminants with never-before-seen results. The Berkey Fluoride Filters (PF2) work as a post filter to the Black Berkey and remove targeted harmful contaminants such as Fluoride, MBTE, Pre-oxidized Arsenic III and Arsenic V, and other heavy metals. The result is crystal clear, great-tasting drinking water! The four Black Berkey Filters (BB9) and four Berkey Fluoride Filters (PF2) are compatible with all Berkey systems and have an incredible lifespan of 3,000 gallons per element. That's a total of 12,000 gallons for a four-filter system! Don't settle for ordinary water filtration, take control of your drinking water with the Berkey Water Filter System with Black Berkey and Fluoride Filters.