Now you can enjoy unmatched UltraWater protection in any ionizer! The UltraWater starts with the BioStone Plus compressed carbon block, we then turbocharge it with UltraWater Wrap technology ensuring unmatched reduction. Up to 99.9% of virtually all contaminants, including Chloramine, Pharma, heavy metals and the toughest to remove contaminants like chromium IV and arsenic. Add Scale Guard protection and it out performs any other purifier replacement filter we know of. Clearly your best choice. (Rated for 1000 gals) This particular water purifier replacement requires an external housing (not included).