Merck Millipore Millex™ Sterile Syringe Filters: Durapore™ PVFD Membrane. Ready-to-use, syringe-driven units designed for sterilizing and clarifying sterile solutions are available in 0.1, 0.22, 0.45 and 5.0µm pore sizes. Pricing and Availability. Cytiva Whatman™ Puradisc PES Syringe Filters: Nonsterile.