Chqistex tm e-ptfe porous membrane combine high flow rate and high filtration efficiency, enabling high rates of airflow while remaining impermeable to water, aerosols, and particles. Features: 100% pure p.T.F.E. 0.2 to 5um reference pore size Wide range of air flows Hydrophobic Unaffected by common chemicals, ph range 0-14 Low friction High porosity with superior air permeability property