1、Made from cotton, activated carbon, and iron exchange resin, can effectively remove hair, debris, dirt, and other particles in water. 2、The activated carbon has more pores and quicker absorbing speed, more durable than ordinary carbon. 3、The diameter of the cat water fountain filter is 10cm/ 3.9inch, and the diameter of the center circle is 2cm/ 0.78inch. 4、Broad compatibility, suitable for most pet water fountains, always provide fresh and clean water for cats and dogs. 5、Please wash the filter before use, and change filters every 2-4 weeks, for the sake of pets\u0027 health. Features： Made from cotton, activated carbon, and iron exchange resin, can effectively remove hair, debris, dirt, and other particles in water. The activated carbon has more pores and quicker absorbing speed, more durable than ordinary carbon. The diameter of the cat water fountain filter is 10cm/ 3.9inch, and the diameter of the center circle is 2cm/ 0.78inch. Broad compatibility, suitable for most pet water fountains, always provide fresh and clean water for cats and dogs. Please wash the filter before use, and change filters every 2-4 weeks, for the sake of pets' health. Specifications： Color: White Material: Polyester, charcoal, and iron exchange resin Product Size: 10 * 10 * 2cm/ 3.9 * 3.9 * 0.78inch Product Weight: 21g/ (Single One) Note： Please check the size before order. Package List： 4 * Filter 4 * Filter