Our Replacement Filters Cartridges are made of premium Polymer Active Carbon, Remove bad tastes and odors, keeping water fresh from pet fountains,efficiently protect your pet healthier 4-layer High-efficiency Filtration: The Cat fountain filters made of high quality double layer cotton, activated carbon and Ion exchange resin. Cat filters fountain can catch hair and debris, filters heavy metals, improve water quality. Every filter individually packaged and sealed to maintain high quality. How to Use Pet Water Fountain Filters: Note: To prevent the activated carbon dust from shedding into water. Please soak the cat water filters in water for 2 minutes and rinse it thoroughly under running water before using it. Then install the pet fountain filters into the cat fountain. Suggested to replace it 2-4 weeks to keep the water clean and fresh. Quantity delivered: 8 pieces Product color: white Product size: 125 125 10mm