Whatman Puradisc FP 30 mm CA Syringe Filter, 0.2 µm, 50 Pack
CA (Cellulose Acetate) Syringe Filters 25mm Diameter 0.22μm Pore Size for Protein Filtration by Allpure Biotechnology (Cellulose Acetate, Pack of 100): Amazon.com: Industrial & Scientific
Kinesis KX Syringe Filter w/ Prefilter, Cellulose Acetate, 30 mm dia., 0.45 µm; 500/pk from Masterflex