Millex-GP Syringe Filter Unit, 0.22 µm, polyethersulfone, 33 mm, gamma sterilized A 33 mm diameter sterile syringe filter with a 0.22 µm pore size hydrophilic Polyethersulfone (PES) membrane. Comes in a pack of 250.; find Millipore-SLGP033R MSDS, related peer-reviewed papers, technical documents, similar products & more at Sigma-Aldrich