Acrodisc® PTFE Membrane Syringe Filter, 13 mm dia, 0.45 µm Pore Size . Syringe Filter, 13 mm dia, 0.45 µm Pore Size, PTFE Membrane, Polypropylene Housing, Borosilicate Glass Prefilter, Non-sterile, Ultimate in Chemical Compatibility For Filtering Harsh Chemicals That Destroy Other Membrane Materials