【For Your Cat's Health】:The cat fountain filters can filter hair, heavy metals, and improve the taste of the water so that pets can drink clean and fresh water all day, which helps to increase water consumption and reduce the risk of urinary tract infections.【Frequency Of Replacement】:To prevent the activated carbon dust from shedding into water, please soak the filter in water for 2 minutes then rinse thoroughly under running water before using. 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.【3-Laryer Protection】:Each filter is composed of a cotton layer, activated carbon, and an ion exchange resin.Size:6 packPet Fountain Replacement Carbon Filters Suggest : 1.Replacing Charcoal filters every 2 to 4 weeks to keep the water clean. 2.Replace more frequently if multiple pets using the fountain, rinse filter with water thoroughly before use. 3.A small amount of carbon dust may be released for the life of filter which is not harmful to your pet.