MF-Millipore ® Membrane Filter, 0.45 µm pore size, 25 mm diameter, mixed cellulose esters (MCE) membrane, hydrophilic, white, 100 discs. View Pricing. AN3H04700. Polypropylene Prefilter, hydrophobic, 30 µm, 47 mm, This is a 30.0 µm pore size polypropylene prefilter constructed of 100% virgin polypropylene media.