This cat fountain filter is composed of activated carbon, ion exchange resin and non-woven fabric, which can filter hair, heavy metals, improve the taste of water, and allow pets to drink clean and fresh water all day long. The Cat Fountain Filter provides clean, fresh water for your pets, helps increase water consumption and reduces the risk of urinary tract infections. Please soak the filter in water for 2 minutes before use and rinse thoroughly under running water. Depending on the drinking frequency of your pet and the number of pets using the cat fountain, please replace the filter every 2 to 4 weeks and the sponge every 4 to 8 weeks. Colour:Photo Color Material:cotton Package Contents: 1set x Cat fountain filter (8xround filter element + 4xfilter cotton) 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.