Compatibility - This cat water fountain filter replacement and water pump filter are designed for use with the WF20/CF20 wireless pet water fountain. The filter size matches the original exactly. Choosing this replacement helps maintain clean and fresh water for your pet. Triple Filtration System - This cat water fountain filter features a three-stage filtration system that includes 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 provide cleaner, healthier water. Water Pump Filter - This cat water filter set includes 9 high-density sponge filters for the water pump. These sponges help catch debris and pet hair to prevent clogging and protect the pump, potentially extending the life of the fountain’s pump. Instructions for Use - To maintain fresh and hygienic drinking water, replace the filter every 2 to 4 weeks depending on the number of pets. Before installation, soak the filter in water and rinse for 2 minutes to optimize performance. The filter uses activated coconut shell carbon, a safe and natural material effective at reducing chlorine and heavy metals. Material: Non-woven fabric Color: White + Black Package Contents: 9 x Filter Elements 9 x Pump Sponge Filters Note: Light reflection and differences in display screens may cause slight variations between the color shown and the actual product. Measurement may vary by +/- 1-3 cm.