Replacement Filters, Set of 10, with Replacement Sponges Compatible with 2.1L Cat Water Fountain PLWF002/ WF002-11M/WF002-11W/WF002-11G. Size: Replacement Filter 18.0 x 9.5cm, Sponge 2.5 x 2.0cm *Please check the filter size before purchasing. *This is a compatible product, so please purchase only if you understand this. Three-layer structure: A three-layer structure with a layer of coconut shell activated carbon sandwiched between high-density micro cotton. It filters out not only pet hair and dust that are difficult to see with the naked eye, but also heavy metals and chlorine. This allows cats and dogs to drink clean water, reducing the risk of urinary tract infections. How to use: Before use, rinse the filter with water for 3-5 minutes to remove carbon dust and dust. Place the non-woven fabric side of the filter facing up, align the convex side of the filter with the corresponding slot, and set it in the water dispenser. It is recommended to replace the filter every 1-2 weeks. *The replacement period may vary depending on the usage situation.