Super five-fold filtration: 1. Pre-filter to filter hair and other impurities. 2. High-density mesh to filter small impurities in water. 3. Ion exchange to filter heavy metal impurities. 4. Activated carbon to filter odor and small molecular impurities. 5.8D filter cotton Filter fine molecular impurities. Bring the best water quality to your pet. Replacement cycle: The best replacement cycle is once every 4-5 days. [More Professional Filtering] The cat water fountain filter can effectively filter impurities, purify and soften the water quality, and prevent the water pump from clogging. High Quality of Cat Fountain Filters: Each filters is composed of cotton ion exchange resin, activated carbon and cotton mesh.They catch hair and debris, filter heavy metals, improve water quality, which is more healthier than other filter materials. Use Advise: please soak the pet fountain filter in water for 2 minutes and rinse it thoroughly under running water before use to prevent the activated carbon dust from shedding into water. Every pcs individually packaged and sealed to maintain high quality. Color: white + blue Material: Cotton Package Contents: 5 x Cat Water 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.