PTFE Syringe Filters consist of a polytetrafluoroethylene (PTFE) membrane and a polypropylene overmolded housing. Available in 13 mm and 25 mm diameters and 0.22 μm and 0.45 μm pore sizes. PTFE is the membrane of choice for use with aggressive solvents, liquids, and gases that can attack other membranes.