Perfect Compatibility: 8 counts small filters cartridges Replacement compatible with Nicrew Slim Filter 3 Stage Filtration: Better thickness dual-sided mesh and Bio Sponge provides better filtration, Ultra-Activated carbon to keep clean and healthy aquarium environment Coconut Shell Activated carbon: Compare with ordinary carbon, ours can effectively filter and faster absorb impurities in the water to keep the clean water source and provide the healthy growth environment for fish Quick Install: Turn off the filter and remove the used cartridge and flush the new cartridge under water to remove dust. After rinsing, insert the cartridge into the flushing chamber and make sure the filter cartridge fits completely into the chamber Professional After-sales service: We recommend that you replace the filters every 2-4 weeks to maintain water quality (depends on the environment of the aquarium system), Please assure the model of your filter before choose the filter cartridges Aquarium Filter Cartridges for Fish Tank