... of the total space in the material,so our foam air filter has good permeability,it can filter and deadening effectively ... comply with ROHS standards. Our pore size of foam air filter:10PPI,15PPI,20PPI,25PPI,30PPI,35PPI,40PPI,45PPI,50PPI ... to the drawings. Our foam air filters are widely used in air filter industries and air purification industries like electrical appliances,electronic products ...