Silver Membrane Filter, 0.45 µm, 25 mm. Product Number. Product Description. SDS. AG4502550. This is a 25 mm Hydrophilic Pure Silver membrane filter with a 0.45 um ( 0.45 micron filter ) pore size. Used for air monitoring of carbon black, coal tar products, coke oven emissions & silica. Referenced by NIOSH for collecting airborne contaminants.