Compatibility - This cat water fountain filter replacement and water pump filter are perfect for the WF20/CF20 wireless pet water fountain. The size of the cat water fountain filter is exactly the same. Choosing this pet water fountain filter will solve all your worries! Triple Filtration System - This cat water fountain filter features a triple filtration system that includes non-woven fabric, activated carbon, and ion exchange resin, which helps to remove odor, soften water, and improve the taste and quality of your petand#39;s drinking water. Meanwhile, the pre-filter sponge captures pet hair, dirt, and food particles, providing your pet with pure and healthy water. Water Pumb Filter - This cat water filter comes with 9 water pump sponge filters made of high-density sponge. The main function is to filter the debris and hair in the water again to prevent clogging and damage to the pump and extend the service life of the fountain pump! INSTRUCTIONS FOR USE - To keep the drinking water and hygienic, it is recommended to replace the pet water fountain filters every 2-4 weeks, depending on the number of cats in your home. Before replacing the filter Elements, to maintain the filtration effect, please soak the cat fountain filter Elements in the water and rinse it for 2 minutes. Pet fountain filter uses activated coconut carbon as the filter material, which is a very safe and non- plant material. It is mainly used to remove heavy metals and residual chlorine in the water. Material: non-woven fabric colour: white+black Package Contents: 9 x Filter Elements 9 x Filter Cotton Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.