Compatibility - This cat water fountain filter replacement and water pump filter are compatible with the WF20/CF20 wireless pet water fountain. The size matches the original filter exactly. This replacement ensures reliable performance for your pet's water fountain. Triple Filtration System - The cat water fountain filter features a three-stage filtration system composed of non-woven fabric, activated carbon, and ion exchange resin. This combination helps reduce odors, soften water, and improve the taste and quality of your pet's drinking water. The pre-filter sponge traps hair, dirt, and food particles, helping to deliver clean and healthy water to your pet. Water Pump Filter - This cat water filter includes 9 high-density sponge filters designed to capture debris and pet hair before they reach the pump. These sponge filters help prevent clogging, protect the pump, and extend the lifespan of the water fountain’s pump. Instructions for Use - To maintain fresh and hygienic drinking water, replace the filter elements every 2 to 4 weeks depending on usage and the number of pets. Before installation, soak the filter element in water and rinse for 2 minutes to optimize filtration performance. The filter uses activated coconut shell carbon, a safe and natural material effective in reducing chlorine and heavy metals in water. Material: Non-woven fabric Color: White + Black Package Contents: 9 x Filter Elements 9 x Sponge Filters Note: Light reflection and differences in display screens may cause slight variations between the color of the item in the photo and the actual product. Measurement may vary by +/- 1-3 cm.