100% pure P.T.F.E. Impermeable to water aerosols and particles Pore size(micron):0 ... resistance, wide operatingtemperature ranging from -400°F to +500°F (-200°C to +260°C), excellentair permeability, vapor transmission, ... cannot rival. Features: 1) 100% pure P.T.F.E. 2) Unaffected by common chemicals, pH value range 0 ... material 5) Biotech, sensor, and optical materials E-PTFE Filter Membrane