The Ion-X Pet Fountain Filters are designed to ensure your pet's water remains clean and fresh, contributing to their overall health and happiness. The unique dual filtration system combines the power of activated carbon and ion-exchange filters. The filter, featuring both a carbon and ion-exchange resin, removes any bad tastes and odors while keeping the water soft to help prevent mineral buildup. These filters are specifically designed for the PetSafe Outlast Cat Fountain and Viva Pet Fountains, providing a perfect fit and ease of maintenance.