PERFECT FIT: This cat fountain filter fits stainless steel 67 oz/2L, 101 oz/3L, 108 oz/3.2L, 135oz/4.0L pet fountains. Cat fountain filter measures 2.99 x 1.69 inches, sponge measures 3.15 x 1.1 inches. Depending on the frequency of your pet's drinking water and the number of pets using the fountain, it is recommended to clean it once a week and replace it 1 to 2 times each time to maintain fresh and clean water. Easy to install and clean: This pet fountain filter replacement is easy to remove and apply, saving a lot of time when cleaning! Please soak the pet fountain filter and sponge in water for at least 3 minutes before use to stimulate the flow of the cat fountain filter For best filtering results, rinse thoroughly with tap water. This will keep your cat's water fresher for longer. [Triple Cycle Filtration]The cat fountain filter replacement adopts a triple filtration system of activated carbon, ion exchange resin, and non-woven fabric. Together they effectively filter impurities such as hair and heavy metals while improving the taste and quality of the water. Colour:Photo Color Material:Cotton Package Contents: 1 set x cat fountain filters Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.