Compatible: Compatible with 1.6 - 3L flower fountains. But not suitable for the Catit fountain. Please measure the dimension of your fountain before purchasing. Dimensions: outer diameter 125 mm, inner diameter 35 mm, 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 ensure water quality and improve the taste of the cat's fresh water. Easy to use: Rinse the filter with water before using it, easy to mount on the fountain. Set of 8 in a box: Economical Cat water fountain filters. We recommend replacing the filter every 2-4 weeks. Process 1, premium non-woven fabric and cotton mesh, it effectively removes hair, debris and impurities in the water , minimizes the threat of pests. Process 2, high quality premium activated carbon, it is made from natural coconut shell, eliminates residual chlorine and other infectious microorganisms. also removes odors, purifies drinking water and further improves taste, allows our pets to drink healthy water. Process 3, ion exchange resin, it removes ions of heavy metals and softens water, makes our pets love drinking water. The three filtration processes and high-quality materials of the cat fountain filter can improve the water quality and taste of fresh water. compatible with most water fountains from 1.6L to 2.4L. NOTE: DOES NOT FIT CATIT FOUNTAIN. Size: outer diameter is 12.5 cm/4.93 in inner diameter is: 3.5cm/1.38in Please check carefully whether the filter size matches your cat water fountain before purchasing. Individual PE bag for each filter, long storage time and more practical. 8pcs replacement filters are more worthy of your possession. Tips: 1, Rinse thoroughly the filter under running water before use. 2, Pet fountain filters should be changed every 2-4 weeks, depending on frequency of use.