Aquasana Replacement Filter Cartridge for Shower Filters Replacement filter for Aquasana Shower Filters: AQ-4100, AQ-4125, AQ-4105 Use genuine Aquasana replacements only - untested replacements are not certified for performance capacity or contaminant removal Replacements made easy - no tools or plumber required. Simply twist, remove, and replace Breathe easy - removes chlorine and other chemicals from your shower steam for better quality air while you shower NSF certified to reduce harsh chlorines and other chemicals for softer, more moisturized skin and hair No change in water pressure - unique up-flow design prevents clogging and channeling