Manufactured exclusively for Hagen's Fluval FX5 and FX6 Filtration Systems, these foam blocks perform mechanical filtration, the crucial first stage in the filtration process. These foam filter pads capture large particles and are custom fit to prevent bypass. They enhance biological filtration, and are ideal for freshwater and marine aquariums. For use with Fluval FX5 and FX6 External Canister Filters.
