Tetra Whisper Bio-Bag Cartridge - Large - 3 pk. - AssembledTetra Whisper Bio-Bag Cartridge - Large - 3 pk. - Assembled Clear water made simple.They're tough on debris:Ultra-activated carbon absorbs odors and discoloration better than competing brands.Dense, dual-sided mesh catches debris and fish waste.More debris-trapping mesh than other products. Easy on you.Convenient, pre-assembled Bio-Bags are ready to use. Simply open, rinse, and place in your Whisper Power Filter. Assembled Whisper Bio Bags are ready to install, simply rinse and slip into the appropriate slot. Removes odors and discoloration. Fits Whisper Power Filters 20i, 40i, C, 20, 30, 40, and 60. Also fits Tetratec power filters. Be sure to add me to your favorites list!