The Everpure S-101 water filter is a quick change replacement cartridge for the Everpure ROM II RO System and Everpure ROM III RO System, Carbon cartridge prefilters chlorine taste and odor, Sanitary quick-change design makes maintenance easy, Reduces chlorine tastes and odors, Instructions:, Flush the""A"" cartridge per Installation and Use Manual, S-101 Prefilter Cartridge""A"" should be changed every 6 months, It is Not possible to be specific about Gallonage limits because turbidity and other aspects of water quality are unpredictable, SKU: CWD603