PACKAGESet of 12 filters and compatible with most 84oz/2.5l round pet fountains. Important for cat health. TRIPLE FILTRATIONComposed of a cotton layer, activated carbon and an ion exchange resin. Effectively to filter hair, heavy metals, keeps water fresh and improve the taste of the water. KEEP YOUR PET HEALTHY Every filter for cat fountain is composed of a cotton layer, activated carbon, and an ion exchange resin. It can effectively remove impurities, filter hairchlorine, heavy metals, and odors. Get high-quality drinking waterhelps to increase water consumption and reduce the risk of urinary tract infectionsmake pets live longer and healthier. RECOMMENDATIONSTo prevent the activated carbon into water, please soak the filter in water for 2 minutes and rinse it thoroughly under running water before use.change the filter according to your pet's drinking frequency , 1 to 2 weeks in summer and 2 to 4 weeks in winter. If multiple cats are using the fountain, more frequent replacement will be necessary.