Polycarbonate Track-Etched Membrane Filters / 0.2 µm / 25 mm Discs. These hydrophilic polycarbonate track-etched filters are manufactured from high quality polycarbonate film using track-etch technology. They have a sharply defined pore size of 0.2 µm with a pore density of 5.0E+08 cm². Pack of 100 white 25 mm discs that have a high chemical