[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 hairs and debris to keep water clean. Activated carbon removes chlorine and odor, helping purify and freshen water. Ion exchange resin helps filter heavy metals and improve water taste. [Filter Sponge & Pump Sponge] High-density pre-filter sponge captures additional impurities to enhance filtration performance. High-density pump sponge prevents particles from entering the water pump, helping extend pump life. [Replace Filter Regularly] Replace the filter and sponges every 2 to 4 weeks. More frequent changes are recommended if you have multiple pets. [Warm Tips] Before installation, soak the filter for 5 minutes and rinse thoroughly to reduce carbon dust and maintain water cleanliness. Product Benefits: Removes impurities Colour: As shown in photo Material: Polyester Specification: 12 sets 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: Lighting reflections and display settings may cause slight color variations between the image and the actual item. Measurement error is permitted within +/- 1-3 cm.