1>Foam filter,good for Aquarium filtering 2>good air permeability 3>polyether foam, reticulated, open cell(10ppi---70ppi) Foam filter products widely used in aquarium filtering, water filtering, air filtering, packing and other business .The polyurethane sponge has different mesh(8ppi-60ppi), high resilient ,good colors and good air permeability .Widely used for aquarium filter, water pump and ...