Compatible: Compatible with 1.6 - 3L flower fountains. But not suitable for Catit fountain. Please measure the dimension of your fountain before purchase. Dimensions: outer diameter 125mm, inner diameter 35mm, thickness 10mm. Improve water quality: Three filtration methods can remove impurities. The outer polyester layer on each filter captures hair and debris. Three stages of filtration ensure water quality and improve the taste of fresh cat water. Easy to use: Rinse the filter with water before use, easy to mount on the fountain. Pack of 8 in a box: Economic Cat water fountain filters. We recommend replacing the filter every 2-4 weeks. 100% Satisfaction Guarantee: 60 Days Money Back, 24 Months Warranty. If you have any questions about our product, please contact us at any time! We will do our best to help you!