Compatibility: These cat water fountain filters are compatible with the Smartoo 152oz/4.5L wireless cat water fountain, helping pets enjoy a better drinking experience. Quadruple Filtration: The filter features activated carbon, ion exchange resin, maifan stone, and non-woven fabric to effectively reduce odors, remove heavy metals, and soften water. Regular Replacement: For optimal performance, replace the filter every 2–4 weeks. If you have multiple pets, consider replacing it more frequently. Warm Tips: Before use, immerse the filter in water for 2 minutes and rinse thoroughly to achieve the best filtration results and ensure clean, fresh water for your pet. Important Notes: If the pump is not working properly, it may be due to low water level or debris such as pet hair entering the pump. Make sure there is sufficient water and clean the pump as needed. Improved Taste: These filters help reduce the taste and odor of chlorine in tap water, making it more appealing to cats. Quantity: A: 9 Sets / B: 18 Sets Color: As shown Material: Non-woven fabric Package Contents: 9 x Cat Water Fountain Filters, 9 x Sponge Foam Filters / 18 x Cat Water Fountain Filters, 18 x Sponge Foam Filters Note: This package includes only the items listed above. Other products are not included. Note: Lighting and display differences may cause slight variations in color between the image and the actual item. Measurement error is allowed within +/- 1-3 cm.