Large dust holding capacity,low resistance,used for active carbon,technic,can adsorb peculiar smell,mist,etc.coarse ... aluminum.4:Mesh:3layers aluminum meshes+active carbon filtration cotton.5:Application:Used for central air conditioner and air conditioner ... filtrationg.6:Advantage:large dust holding capacity,low resistance,used for active carbon,technic,can adsorb peculiar smell,mist,etc.coarse ...