Description. 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. Available in 4, 13, 25, 33, and 50 mm diameters with a variety of membranes, Millex™ sterile syringe filters are ideal for sterilizing organic solvents, aqueous solutions or air/gas.