You can have the purest drinking water with the ZeroWater ZR-006 Replacement Filter Cartridge. The white plastic cartridge is designed to remove all detectable dissolved solids from your tap water, so you can get a great tasting and healthier water. The cartridge filters five stages of water, namely carbon, charcoal, reverse osmosis, and alkaline ionizer. It is compatible with Aqua Optima Evolve and comes in a 4 pack. Give your family the best water drinking experience, get ZeroWater ZR-006 Replacement Filter Cartridge today.