Millipore. 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 50. MSDS (material safety data sheet) or SDS, CoA and CoQ, dossiers, brochures and other available documents.