EXW price ptfe membrane filter 0.22 um Amazon Syringe Filters - Sigma-Aldrich Medical Millex-GP Syringe Filter Unit, 0.22 µm, polyethersulfone, 33 mm, sterilized by gamma irradiation, A 33 mm diameter sterile syringe filter with a 0.22 µm pore size hydrophilic Polyethersulfone (PES) membrane.