Cat Fountain Filter, 4 Pieces Drinking Fountain Filter, Cat Fountain Filter with Activated Carbon and Resin with Triple Filtration Efficient protection: this filter cat fountain uses double filtration. The high-density cotton layer filters out hair and other deposits, and the activated carbon and ion exchange resin help you filter out most impurities and heavy metals while removing odours, making every drop of water cleaner and healthier. Package includes: 4 drinking fountain filters for cats, enough to meet the needs of your replacement. Each filter water fountain cat is individually packed, this can ensure the tightness of each filter for water fountain cat and maintain high quality. Note: Soak the cat fountain filter in water for 5 minutes before use and rinse it to prevent surface dust from falling into the water. After your pet's drinking frequency and the number of pets using the fountain, change the filter every 2-4 weeks.