Patented Aqueon dual-sided dense-floss cartridges contain over 25% more activated carbon than the leading brands. These unique cartridges were designed to ensure even distribution of carbon throughout for more thorough filtration and longer cartridge life. High quality activated carbon keeps water clean Align cartridge bottom key slot for an accurate fit inside the filter Rinse under water to remove carbon dust before replacing For optimal performance, change approximately every 4 to 6 weeks Do not clean Bioholster when replacing the cartridge as it contains beneficial biological bacteria SMALL//3 PACK/6 PACK - Fits Aqueon mini bow aquarium filters LARGE/1 PACK/3 PACK/6 PACK/12 PACK - Fits Aqueon quiet flow 20,30,50, and 55/75 filters MEDIUM/1 PACK/3 PACK/6 PACK/12 PACK - Fits Aqueon quiet flow 10 filter
