[Quadruple Filtration]: Quadruple filtration softens water quality, deep purification and flavor enhancement, quadruple filtration system, 24-hour uninterrupted circulation filtration, intercepts various impurities layer by layer, protects pet health It can filter cat hair, debris, coarse dust, heavy metals and other odors and impurities, providing only clean and healthy water. High Compatibility: 12.5cm * 12.5cm. Better replacement: Compared with ordinary activated carbon filter, our filter has longer life and less frequent replacement. We recommend that you change the filter every four weeks to keep the water clean. Easy to use: Please fully soak the fountain before use. Then plug the cat fountain filter into the water dispenser. Provide cats with cool, healthy water. Instructions for use: In order to ensure better filtering effect, the filter element should be replaced once a month. The filter element should be washed with water before use Product Description: Material: non-woven fabric + coconut shell activated carbon + ion exchange resin Note: Please allow 0-2cm difference due to manual measurement. Thanks for your understanding. Monitor calibration methods are different. The color of the product shown in the photo may be slightly different from the actual product. Please refer to our size before placing an order. Quantity delivered: 4 pieces