... open cell(10ppi--70ppi) 1: foam filter has different mesh size (8ppi-60ppi),2: foam filter, polyurethane foam materials .reticulated, open ... colors and good air permeability .Widely used for aquarium filter, water pump, air filter and other filtering business .4:It's durable ... in water and low cost .5: Pond filter, widely used for filtering industrial .water treatment . foam ...