Perfect MatchCat fountain filters match a wide range of cat water fountains, applicable fountain styles are listed in the product images, please confirm if it matches your cat fountain before purchasing to avoid wrong purchase. Premium 4+4 Pack4-pack of premium pet fountain replacement filters and 4 pre-filter sponges, individually packaged and sealed to maintain high quality. Keep Your Pet HealthyThe filter uses plastic as the bottom shell, composed of cotton layer, activated carbon and ion exchange resin. They can filter hair, heavy metals, and improve the taste of the water so that Let your pet drink clean and healthy water. RecommendationsTo prevent the activated carbon dust (which will not harm your pets) from shedding into water, please soak the filter in water for 2 minutes and rinse it thoroughly under running water before use. ReplaceRinse the filter with running water every time you change the water of the fountain and according to your pet's drinking frequency and the number of pets using the fountain, change the filter every 2-4 weeks.