Iso9001 pore size 0.2um PTFE membrane filter manufacturer Whatman Nuclepore Hydrophilic Membrane, 0.4 µm Pore Size, 90 mm Circle, 25 Pack, 10417118. Regular Price $168.53 Price $146.55. Add to Cart. Add to Wish List. Whatman 7182-009 Cellulose Nitrate Membrane Circle, plain, 0.2 um pore size, 90 mm, 25 per pack. Regular Price $128.75 Price $111.96.