Doulton W9121302 Imperial Super Sterasyl Ceramic Filter Candle Candles have a domed end and a plastic mount on the top to fix them into the filter housing W9121302 cleanable filter elements are designed toreduce suspended solids, pathogenic bacteria, organic chemicals, and improve taste and odor At the heart of every Doulton ceramic filter is the "Sterasyl" silver impregnated ceramic micro filter