Key item features 1.Effective Contaminant Reduction: The PF-2 elements effectively reduce fluoride, arsenic V, pre-oxidized arsenic III, and other residual heavy metal ions. 2.High Reduction Rates: Achieves fluoride reduction rates of over 95%, with effluent concentrations of less than 50 ppb, equating to a reduction of more than 99.75%. 3.Durable and Safe Materials: Constructed from BPA-free, non-leaching Polypropylene #5, ensuring safety and longevity. 4.Long-Lasting Performance: Each set of two PF-2 elements has a lifespan of approximately 1,000 gallons (3,785 liters) or up to one year, depending on water quality and usage. 5.Easy Installation: These elements attach to the bottom of the Black Berkey Purification Elements and reside in the lower chamber of the Berkey system. 6.System Compatibility: Designed for use with Black Berkey Elements in Berkey systems such as Travel, Big, Royal, Imperial, Crown, and Berkey Light. Not compatible with Super Sterasyl Ceramic Filters or the Go Berkey Kit.