【Compatibility】 Compatible with 1.6 L - 2.4 L cat water drinking fountain. NOTE: NOT SUITABLE FOR CATIT FOUNTAIN.Please measure the size of pet fountain and check the size of replacement filter before purchasing.Size：external diameter12.5cm/4.93in internal diameter:3.5cm/1.38in 【Improve water quality】 Three filtration methods can eliminate impurities. The outer polyester layer on each filter captures hair and debris. The three filtration stages guarantee the quality of the water and improve the taste of the fresh water of the cat 【Replacement suggestions】 It is recommended that you change the filter every three-four weeks to keep the water clean.Please rinse the filter before first using 【Premium Material】 Pet water fountain filters are made of high-quality activated carbon, premium cotton mesh, Non-woven fabric which effectively remove impurities 【High Quality and Service】Our filters are highly performance and of premium quality.we provides 365 days after-sales service for all products. For any questions or product problems, welcome to contact our professional & 24 hours online services team, Manufacturer: ECOSI