Fluval Foam 2-Pack (Fluval A-222) for Hagen Fluval 204, 205, 304 and 305 filtersFor freshwater and marine environmentsEach filter pad is 8-5/8" X 2-7/8" X 7/8"Fluval Foam Inserts perform mechanical filtration, the first crucial step in the filtration process. Foam pore size provides efficient water flow with less clogging for long lasting filtration.