Corning® syringe filters, cellulose acetate membrane (surfactant-free), diam. 28 mm, pore size 0.2 μm CLS43 Corning® syringe filters, cellulose acetate membrane (surfactant-free), diam. 28 mm, pore size 0.45 μm CLS431221 Corning® syringe filters, cellulose acetate membrane (surfactant-free), diam. 28 mm, pore size 0.8 μm CLS431224