Tetra Whisper ATS26170 Assembled BioBag Filter Cartridges, Large 6 Count Large, 6-Count (2 pack of 3-Count) Conveniently Assembled and Ready-to-Use, Easy to Assemble, Easy to Replace Keeps water crystal clear. Mesh Catches Debris And Fish Waste. Removes odors and discoloration. Fits whisper power filters 20i,40i, c,20,30,40, and 60.