Fluval U3 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. Suitable for freshwater, marine or reptile environments. Key Features: •For Fluval U3 Underwater Filter •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 •Suitable for freshwater, marine or reptile environments •Includes 2 foam pads