About This

• Finest-Filters compatible replacement foam and polycarbon filter cartridges are made from the same material as the Fluval originals.
• These filter pads are made to fit the Fluval U4 range of internal filters
• The plain filter sponges contain the biological cultures, biologically and mechanically filtering the aquarium water
• The polycarbon filter cartridges remove small particles from the water, and the activated carbon chemically filters the water of impurities
• Please Note: This is not a Fluval Product. This is a Finest-Filters alternative which serves the same purpose as the original brand.