The Doulton W9123053 UltraCarb 10-inch Filter Candle features four stages of filtration in a single cleanable cartridge. It reduces suspended solids, chlorine, lead and other trace contaminants, as well as improving taste. Also known as Mountain Pure Water #MT661-RFC, the carbon core improves taste, while also reducing particulates and other chemical contaminants overall. In addition to being NSF certified, the W9123053 water filter has been tested and approved by the World Health Organization--for excellence you can depend on. From the Manufacturer The Doulton W9123053 UltraCarb Filter Candle features a Sterasyl ceramic outer shell and carbon block core with ATS resin.