Compatible: Compatible with 1.6 - 3L flower fountain. But not suitable for Catit fountain. Please measure your fountain dimension before purchase.Dimensions: outer diameter 125mm, inner diameter 35mm, thickness 10 mm. Improve water quality: Three filtration methods can remove impurities. The outer polyester layer on each filter captures hair and debris. The three stages of filtration guarantee 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.