Fluval U4 Foam Insert / Foam Pad - 2 Pack (A488) The replacement Fluval U4 Foam Pads are designed for: Fluval U4 Underwater Internal Filter Fluval U4 Foam Pad captures large particles and debris for effective mechanical filtration, the crucial first stage in the filtration process. It is custom-made to fit perfectly inside the filter chamber to prevent debris bypass. The foam pad has a pore size that allows efficient water flow, less clogging and long-lasting filtration. Key Features: Captures large particles and debris for effective mechanical filtration Custom-made to fit perfectly inside the filter chamber to prevent debris bypass Has a pore size that allows efficient water flow, less clogging and long-lasting filtration Easy to install
