Feature: 1. EFFECTIVE FILTRATION: Fountain filter consists of a cotton layer, activated carbon and resin to filter lint and residue, remove odors and soften water. The filter is designed with the front side up and the back side down. 2. IMPROVE WATER QUALITY: High density microporous cat fountain filters (pore diameter: 3.5cm/1.4in), effectively clean water, providing clean water for your pet. 3. PERFECTLY COMPATIBLE: Cat fountain activated carbon filters are compatible with 84 ounce, 2.5 liter quadrate cat fountains or pet fountains. 4. INDIVIDUALLY PACKED: Pet cat water fountain filter is individually packaged and sealed to maintain cleanliness and hygiene. 5. PRECAUTIONS: Please soak the cat water fountain filter in water for 2 minutes and then rinse thoroughly under running water before use. Specification: Item Type: Cat Fountain Filters Material: Activated Carbon, Resin Size: Approx. 12.5x12.5cm / 4.9x4.9in Caliber Diameter: Approx. 3.5 cm/1.4in Recommendation: Please rinse the filter thoroughly with water before use. Replace every 2-4 weeks to keep water clean. Use fountains to replace multiple pets more frequently. . Package List: 12 x Cat Fountain Filters Note: 1. 12 pieces of premium activated carbon filter, enough for 612 months, please check the size carefully before purchase.2. Please allow for some errors in manual measurements.