Aquasana Replacement Filter Cartridges for Aquasana Countertop Water Filtration System Replacement filter pack for Aquasana Countertop Water Filtration System: AQ-4000. Includes one of each filter type 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 Only 11 cents per gallon - 11 times the capacity of the leading gravity-based filter pitcher Retains the healthy minerals like calcium, potassium, and magnesium - the healthiest drinking water for you and your family NSF Certified to Standards 42, 53, 401, +P473 to remove 77 contaminants including lead, mercury, pesticides, pharmaceuticals, and more