Check the listing for details. Aqueon Large Replacement Cartridges For QuietFlow Led, Internal 20,30,50,75,. Condition: New. Listed at 6.99 USD. NEW Aqueon Large Cartridge Replacement filter cartridge for Power Filters and Quitflow. Good for: QuietFlow Led Pro Power Filter Size 20,30,50,75Quitflow Power Filter Size 20,30,50,55/75QuitFlow E internal power filter Size 40.QuitFlow Canister Filter Sizes 200,300,400 New Aqueon Large 1,3,6 and 12 packs Sizes: (5"L x 6.5"H) Patented Aqueon dual-sided dense-floss cartridges contain over 25% more activated carbon than the leading brands. These unique cartridges were design to ensure even distribution of carbon throughout for more thorough filtration and longer cartridge life. High quality activated carbon keeps water cleanAlign cartridge bottom key slot for an accurate fit inside the filterRinse under water to remove carbon dust before replacingFor optimal performance, change approximately every 4 to 6 weeksDo not clean Bioholster when replacing the cartridge as it contains beneficial biological bacteria