Doulton Imperial elements are designed to fit in most Industry Standard 10-inch housings and offer a greater flow rate than the Slim-Line filter elements. The Doulton Imperial Sterasyl Ceramic Filter is a self-sterilizing filter that can be re-used over and over again to provide absolute micron filtration down to 0.9 microns at an economical price. The Doulton W9220406 cartridge is open on both ends OBE and fits in standard 10-inch filter housings. The Doulton W9220406 Imperial Hollow Core OBE Filter features a Sterasyl ceramic outer shell with no core. The Doulton Imperial Sterasyl ceramic shell is silver-impregnated ceramic. The incorporation of silver locked within the ceramic structure inhibits the growth of bacteria and gives each cartridge enhanced bacteriostatic and self-sterilizing properties. Doulton Imperial Sterasyl Ceramic Filter W9220406 is ideal for RO guard and post filtration and complimentary to UV systems. The Doulton Imperial Sterasyl W9220406 Ceramic Filter is NSF Certified for Standards 42 & 53. The Doulton Difference Doulton has been a manufacturer and provider of quality water filters and filter systems since 1826. The company is well known for its range of gravity-fed filter systems and ceramic filter options distributing ceramic filtration solutions to 140 countries across the globe. Using naturally-occurring raw materials in its filters Doulton actively promotes environmentally-friendly filtration options designed to provide clean drinking water to all of its users.