Iso-Disc™ Syringe Tip Filter Unit PTFE membrane, pore size 0.2 μm, diam. 4 mm, natural, pkg of 100 ea; Synonyms: PK100 Iso-Disc PTFE-4-2, 4MM X 0.2UM; find Supelco-54143U MSDS, related peer-reviewed papers, technical documents, similar products & more at Sigma-Aldrich