Fluval® Foam Pads are specially designed to fit Fluval® FX5 High Performance Canister Filters. The Pads capture large particles and debris for effective mechanical filtration, the crucial first stage in the filtration process. Custom fit to prevent bypass, they have a pore size that allows efficient water flow with less clogging for long-lasting filtration. For freshwater and marine environments. Three filter pads in a pack.