[Compatibility] Designed for 135 fl oz/4L wireless cat water fountain. [Triple Filtration System] Cat water fountain filters feature a 3-layer filtration system. High-density cotton filters hair and debris to keep water clean. Activated carbon removes chlorine and odor, purifying and freshening water. Ion exchange resin filters heavy metals and improves water taste. [Filter Sponge & Pump Sponge] High-density pre-filter sponge captures additional impurities, enhancing overall filtration performance. High-density pump sponge prevents particles from entering the water pump, helping extend pump life. [Replace Filter Regularly] Replace filter and sponges every 2 to 4 weeks. More frequent changes are recommended for multi-pet households. [Warm Tips] Before installation, soak the filter for 5 minutes and rinse thoroughly to prevent carbon dust from entering the water and to maintain water cleanliness. Product Benefits: Removes impurities Color: As shown in photo Material: Polyester Specification: 12 Set Package Contents: 12 x Replacement Filters 12 x Filter Sponges 12 x Pump Sponges Only the above package content is included; other items are not part of this package. Note: Due to light reflection and differences in display screens, the color in the image may vary slightly from the actual product. Measurement may vary by +/- 1-3 cm.