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. Choosing this pet water fountain filter helps ensure proper function and performance. Triple Filtration System - This cat water fountain filter features a three-stage filtration system including non-woven fabric, activated carbon, and ion exchange resin. It helps reduce odors, soften water, and improve the taste and quality of your pet's drinking water. The pre-filter sponge captures hair, dirt, and food particles to provide cleaner water for your pet. Water Pump Filter - This cat water filter includes 9 high-density sponge filters designed to capture debris and hair before they reach the pump. This helps prevent clogging, protects the pump, and extends the lifespan of the fountain. Instructions for Use - To maintain fresh and clean drinking water, replace the filter 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 as the filtering material, which helps reduce chlorine, heavy metals, and impurities from water. This material is safe and commonly used in water filtration. Material: Non-woven fabric Color: White + Black Package Contents: 9 x Filter Elements 9 x Filter Cotton Note: Light reflection and differences in display screens may cause slight variations in color representation. Measurement may vary by up to +/- 3 cm.