<p>Whisper Bio&#045;Bag Cartridges complete the Whisper Power Filter package for a clean, easy&#045;to&#045;maintain aquarium&#046; Filled with Ultra&#045;Activated carbon, ready to use disposable cartridge remove waste particles, odors and discoloration, and are easily changed once a month&#046;</p><ul><li>Medium Size, 3&#045;pk assembled</li></ul>