The W9240001 is designed for use in Doulton"s pressurized candle filtration systems, The W9240001 Carbon Block filter is a great addition to the HIP2 Duo and HIP3 Triple housing filter units, The Doulton Specialty Replacement Filter Cartridge fits all Doulton short mount Countertop, Undersink and Inline Systems, The filter uses Activated Carbon Block to remove contaminants for up to 6 months or gallons - whichever comes first, Contaminant Removal: Chlorine Taste and Odor, Filter Type: Activated Carbon Block, Filter Life: 6 Months, SKU: CWD3787