MF-Millipore ® Membrane Filter, 0.45 µm pore size, 25 mm diameter, mixed cellulose esters (MCE) membrane, hydrophilic, white, 100 discs. View Pricing. GPWP04700. Millipore Express PLUS Membrane Filter, 0.22 µm pore size, hydrophilic polyethersulfone, 47 mm idiameter.