Pall Gelman HPLC Filter Disc, 0.45 Pore Size. Filter Disc, 47 mm dia, HPLC, 0.45 Pore Size, GHP Membrane, 5 mil Thickness, Useful for a Wide Range of Applications Offers Broad Chemical Resistance to Common Solvents, Naturally Hydrophilic. Manufacturer Part #: 66608. SECO Part #: 66608.