1>Aqua foam filter,PU foam;Reticulated;open cell 2>Aqua foam filter, good for water and air filtering and cleaning 3>Low cost Aqua foam filter,filter parts---filter sponge which widely used in aquarium filtering, water treatment, water pump, pond and so on ...The filter sponge has different mesh(8ppi-60ppi), high resilient ,good colors and good air permeability .Widely used for aquarium filter, ...