*Please note: This product is only available for the Water Fountain of Model PL-WF002 【KEEP YOUR PET HEALTHY】Each filter is composed of a cotton layer, activated carbon, and an ion exchange resin. It can effectively remove hair, heavy metals, and improve the taste of the water so that pets can drink clean and fresh water all day, which helps to increase water consumption and reduce the risk of urinary tract infections. 【RECOMMENDATIONS】To prevent the activated carbon dust (which will not harm your pets) from shedding into water, please soak the filter in water for 15 minutes or rinse it for 30 seconds thoroughly under running water before use. According to your pet's drinking frequency and the number of pets using the fountain, change the filter every 2 weeks.