?Compatible Models?-The Purewell Ceramic Filters can be replacement for ProOne Big+ or Big II Series and Berkey BB9-2 black filters, Travel, Big, Royal, Imperial, Light, Crown Berkey Series. And it is also compatible with Purewell Gravity-fed Water Filter System. Thanks to its exquisite design, this filter achieves great fit and no leakage. The water filter is not sourced by or sponsored by Berkey or ProOne. Purewell is an independent brand. | ?Efficient 3-Stage Filtration?-Our ceramic filters feature a 3-layer design. The outer layer is ceramic, effectively blocking large particulate contaminants; the middle layer is activated carbon, removing 99% chlorine and harmful chemicals; and the inner layer contains silver ions, preventing the growth of other substances after filtration, further reducing harmful substances and ensuring the safety of drinking water. Please flush the filter for 1 min before use by connecting to faucet. | ?Connectable?-Our ceramic filter element can be connected with the white defluorination filter element (like FL-2) to meet your fluoride removal needs, which is not available in other ceramic filters on the market. | ?Safe and Washable?-The replacement for Berkey or ProOne water filter is certified against NSF/ANSI 372 standard for lead-free materials. Furthermore, this filter uses BPA-free housing, ensuring its safety. When sedimentation appear on the surface of the filter element, you can use the included sponge to scrub the surface of the filter element to extend the service life of the filter element, but do not use soap or other cleaning materials (otherwise it will clog/damage the filter pores). | ?Longer Service Life?-Each pair of ceramic filters can provide 10,000 gallons of fresh water. For better performance, we recommend that you replace the filter every 10,000 gallons. However, this may vary depending on your water conditions. Note: That TDS level does not fully indicate the quality of the water and our filters DOES NOT lower TDS value.