[PACKAGE INCLUDES]10 pack filter cartridges for aquarium filter replacement. For optimal performance we suggest to replace the cartridges every 1-2 weeks. You can also rinse the to prolong the serivce time. [FILTRATION FUNCTION]The filter cotton is made of two layers of cotton sponges on both sides and a layer of activated carbon in the middle, which can filter and absorb 99% of the sundries to fish, so as to keep the water source clean and the healthy growth of fish. [ENVIRONMENT MAINTAIN]Please remove used and rinse new cartridges with water to remove the outside dust, then fully seat it into the filter chamber. Replace it every 1 to 2 weeks to maintain a healthy water environment. Protect the health and safety of your fish all the time. [EXCELLENT PERFORMANCE]3-layer design to absorb odors and discoloration.Provide clean and healthy water for your tank.Filtering effect to filter and absorb impurities, especially absorb ammonia and nitrogen in the wate, help to maintain a healthy aquatic environment. [APPLICATION RANGE]Compatible with 3.5w low-water turtle tank filter