About this item 1.2 AUTHENTIC BLACK BERKEY ELEMENTS BB9-2 REPLACEMENT ELEMENTS FOR BERKEY GRAVITY-FED WATER FILTER SYSTEMS- Black Berkey Elements can be used with Big Berkey, Berkey Light, Crown Berkey, Imperial Berkey, Royal Berkey, Go Berkey and Travel Berkey Systems. 2.FILTERS OVER 200+ TYPICAL CONTAMINANTS THAT COULD BE PRESENT IN TAP WATER- Choose only Black Berkey Elements. There are no substitutes for Berkey performance and quality. 3.INDEPENDENT TESTING- Black Berkey Elements are composed of a unique, proprietary blend of multiple media types backed by testing from accredited, third-party labs. Black Berkey Elements are designed to work synergistically and target specific contaminants that far exceed the reduction capabilities of carbon block filters that are solely composed of activated carbon.