100% pure P.T.F.E. Impermeable to water aerosols and particles Pore size ... chemical resistance, wide operatingtemperature ranging from -400°F to +500°F (-200°C to +260°C), excellentair permeability, vapor transmission, ... rival. Features: 1) 100% pure P.T.F.E. 2) Unaffected by common chemicals, pH value ... range 0-14 3) Wide operating temperature: -400°F ~ +500°F (-200°C ~ +260°C)4) Aging deterioration ...