Check the listing for details. Berkey Reduction Elements, Use with Black Berkey Water filter Elements, 2 Pack. Color: White, Condition: New. Listed at 120.99 USD. The Berkey PF-2 Fluoride and Arsenic Reduction Elements absorb the following unwanted elements found in drinking water: Fluoride: Sodium Fluoride, Sodium Fluorosilicate, Fluorosilicic Acid (aka Hydrofluorosilic Acid). Arsenic: V and pre-oxidized Arsenic III. Other residual heavy metal ions. Other Features: Made from safe, non-leaching Polypropolene #5. Sold in a set of 2. Berkey PF-2 Fluoride and Arsenic Reduction Elements are designed to be used in conjunction with the Black Berkey Elements only. Attach to the bottom of the Black Berkey Elements and sit in the lower chamber of the Berkey unit. Number of Berkey PF-2 Elements in the bottom chamber must match the number of Black Berkey Elements in the top chamber; for example, 4 Black Berkey Elements would require 4 PF-2 Filters.