Specifically designed to fit inside the Fluval Nano Filter, the Fluval Fine Foam Pad traps small sediments and debris for effective mechanical filtration, the crucial first stage in the filtration process. Custom-sized, it fits 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. It is suitable for freshwater environments. Package contains 2 Fine Foams.