Filtration efficiencies include 0.1 and 0.2 micron. BETA????? Teflon (PTFE) Membrane. Highly resistant to chemical and thermal extremes, Teflon is an ideal membrane for use in filtration of aggressive chemicals, extreme operating temperatures and where critical filtration is required. Available micron pore sizes 0.03, 0.05, 0.1, 0.2, 0.45, and 1.0