Our Ultrafree ® centrifugal filters with microporous Durapore ® PVDF membranes are available in both sterile and non-sterile versions with 0.1 µm, 0.22 µm, 0.45 µm, 0.65 µm, and 5 µm pore sizes for 0.5 mL and 2 mL working sample volumes. Hydrophilic PTFE