Pack of 20 - Replacement drinking fountain filters for Catit PIXI Compatible with Catit PIXI 2.5L Water Fountain and Cat Fountain Model 43717. Please verify your fountain model before purchasing. These are replacement filters and are not manufactured or sold by Catit. To reduce activated carbon dust, soak the filter in water for 3-5 minutes and rinse thoroughly under running water before use. Replace the filter every 2-4 weeks depending on your pet's usage and the number of pets. Each filter is made with a cotton layer, activated carbon, and ion exchange resin. Effectively traps hair and particles, reduces heavy metals, and improves water taste, promoting cleaner, fresher water for pets and supporting increased hydration and urinary tract health. Product Name: Cat Fountain Filter Material: Non-woven fabric + Activated Carbon Size: 8.4 x 8.4 x 0.9cm, Middle Hole Diameter: 1.7cm Package Included: 20 pcs Cat Fountain Filter Note: This is not an original product. The water fountain is not included.