berkey light gravity-fed water filter with 2 black berkey elements berkey equipped with powerful black berkey elements, the 2.75-gallon berkey light water filter system sits on a countertop or stand, and addresses over 200+typical contaminants that could be present in tap water and raw, freshwater sources like rivers and ponds. the berkey light system is portable and effortless to use—no tools, electricity, or plumbing are required. just pour untreated water into the top chamber and dispense clean, refreshing water from the spigot. we recommend replacing black berkey elements after 6,000 gallons, depending on the quality of influent water. each additional pair of black berkey elements (sold separately) adds an additional 6,000 gallons of typical contaminant reduction to your system before replacement is recommended. if desired, berkey pf-2 fluoride and arsenic reduction elements (sold separately) may be installed on each black berkey element. black berkey elements are backed by independent, third-party testing.