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 combines 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 to 4 weeks. If you have multiple pets, consider replacing it more frequently. Usage Instructions: Before use, soak the filter in water for 2 minutes and rinse thoroughly to ensure best results and provide clean, fresh water for your pet. Important Information: Pump issues may occur due to low water levels or debris such as pet hair entering the pump. Ensure adequate water levels and clean the pump regularly. Improved Water Quality: These filters help reduce chlorine taste and odor from tap water, making it more appealing to cats. Quantity Options: Available in 9-set or 18-set packs Color: As shown Material: Non-woven fabric Package Contents: Each set includes cat water fountain filters and sponge foam filters. The package includes only the items listed; other products are not included. Note: Due to lighting and display differences, the actual color may vary slightly from the image. Measurement variations may occur by +/- 1-3 cm.