The first thing a filter has to deal with is the visible debris moving through the water. These pads are shaped for the Fluval U3 Underwater Filter chamber, so that stage can catch large particles before they pass further into the filtration system.

The pad is custom-made for the chamber to prevent debris bypass. Its pore size is intended to allow efficient water flow, less clogging and long-lasting filtration, and the listing says it suits freshwater, marine or reptile environments.

• For the Fluval U3 Underwater Filter
• Captures large particles and debris
• Custom-made to fit the filter chamber
• Designed to prevent debris bypass
• Pore size allows efficient water flow and less clogging
• Two foam pads included

One thing worth knowing. the maker gives the filter model and broad environment suitability but no pad dimensions or maintenance schedule. Confirm that your filter is the U3 model and use the maker's instructions for changing or cleaning the pad.

Who it's for: fishkeepers and reptile keepers with a Fluval U3 Underwater Filter who need its specified mechanical foam stage.