Nalgene® syringe filter units, disposable, polyethersulfone (PES) membrane. A 25 mm diameter sterile syringe filter with a 0.2 µm pore size hydrophilic PTFE membrane. Comes in a pack of 50. A 13 mm diameter sterile syringe filter with a 0.2 µm pore size hydrophilic PTFE membrane. Comes in a