Check the listing for details. British Berkefeld Doulton W9120133 Fluoride Water Filter Candle Cartridge, 2 Pk. Color: White, Condition: New. Listed at 130.00 USD. Ultra Fluoride Element for Gravity Water Filters Keep your gravity water filter working smoothly and your drinking water tasting great! The British Berkefeld Ultra Fluoride Filter delivers all the expected benefits of a ceramic water filter element, giving superior flow rates in a gravity filter while reducing particles and organics. It has been tested to remove up to 98.9% of fluoride and will absorb a total 1,950 ppm of fluoride. Made for the British Berkefeld gravity filter systems (Duchess, Duke and Prince). Also suitable for Berkey, Phoenix, Purewell, ProOne, Alexapure and other gravity water filter systems. Unlike other gravity filter systems, this fluoride filter element is installed in the upper chamber, so it doesn't sit in your clean, filtered water in the lower chamber.