U series foam block

Fluval U1:

Custom designed, the Fluval U1 foam block fits snugly into the filtration chamber to prevent debris from passing through. The pore size prevents blockage and allows for constant water flow, as well as long-lasting filtration. Suitable for freshwater or saltwater aquariums, as well as reptile habitats.
Main characteristics:

Block dislodges large particles to ensure efficient mechanical filtration
Custom designed so that the foam block fits snugly in the filtration chamber and prevents debris from passing through.

Pore ​​size that prevents blockage and allows for constant water flow, as well as long-lasting filtration.

Fluval U2, U3 and U4:

The Fluval U-Series foam block dislodges large particles for efficient mechanical filtration, which is the critical first step in the filtration process. Custom designed, the Fluval U-Series foam block fits snugly in the filtration chamber to prevent debris from passing through. The pore size prevents blockage and allows for constant water flow, as well as long-lasting filtration.
Main characteristics:

Block dislodges large particles to ensure efficient mechanical filtration
Custom designed so that the foam block fits snugly in the filter chamber and prevents debris from passing through
Pore ​​size that prevents blockage and allows for constant water flow, as well as long-lasting filtration.

All Fluval U series submersible filters:

Fluval U1 submersible filter, for aquariums containing up to 55 L (15 US gal) (A485)
Fluval U2 submersible filter, for aquariums containing 45 to 110 L (12 to 30 US gal) (A486)
Fluval U3 submersible filter, for aquariums containing 90 to 150 L (24 to 40 US gal) (A487)
Fluval U4 submersible filter, for aquariums containing 130 to 240 L (34 to 65 US gal) (A488)