Replacement Period - Every 2 to 4 weeks for better water quality, mainly depending on water condition and the number of pets.4-Stage Circulating Filtration System - The system uses a replaceable round filter to purify the water, remove dirt and food particles . The round filter is composed of Non-woven layers, ABS grid, coconut shell activated carbons and ion-exchange resins. It provides fresh clean water to your lovely pets.Health and Safety: Made of eco-friendly materials, the filters help ensure the water quality and provide healthy and pure water to protect your pet's health.Replacement for Pettie Cat Drinking Fountain Stainless Steel and Colorful Cat Water Fountain with LED Light- The package includes 4 carbon filters.Kind Reminder: Before the replacement, rinse the filters with clean water, and it is better to have a constant and sufficient supply of filters to ensure the water quality.Suggestion:Please replace the filters and clean the fountain regularly.The complete cleaning can be done every two weeks so that you can ensure the water quality.Colour: whiteMaterial: non-woven fabrics, ABS gridSize: 10x10.5cmPackage Contents:4 * Repalcement Carbon FiltersOnly the above package content, other products are not included.Note: Light 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.