Features： Made from premium cotton active carbon and resin can effectively remove hair debris dirt and other particles in water. coconut shell activated carbon adopted has more pores and quicker absorbing speed more durable than ordinary active carbon. diameter of cat water fountain filter is 12.5cm/ 4.9inch and diameter of center circle is 3.3cm/ 1.2inch. Broad compatibility suitable for most round water fountains always provide fresh and water for cats and dogs. Please wash filter before use and change filters every 2-4 weeks for sake of pets health. Specifications： Color: White Material: Cotton & active carbon & resin Product Size: 12.5 * 12.5 * 0.5cm/ 4.9 * 4.9 * 0.19inch (single one) Product Weight: 10g/ 3.5oz (single one) Note： water fountains showed in pictures are not included. Package List： 8 * Filter