Fluval C4 Foam Pads Replacement Media, 2-pack, capture large particles and debris for effective mechanical filtration, a crucial stage in the filtration process. The Fluval C4 Foam Pads Replacement Media prevent bypass, and allow efficient water flow with less clogging for long-lasting filtration. The foam pads help you maintain a healthy and clean environment for your fish. The Fluval C4 Foam Pad was made specifically for the Fluval C4 Power Filter.