25mm ptfe membrane filter 0.2 um Sigma Aldrich 0.2 um filters | Sigma-Aldrich cellulose nitrate membrane, pore size 0.2 μm, membrane diam. 90 mm, filter capacity 54.5 cm 2: Pricing: CLS430771: Nylon membrane, pore size 0.2 μm, membrane area 19.6 cm 2, filter capacity 250 mL: Pricing: CLS430773: Nylon membrane, pore size 0.2 μm, membrane area