100% pure PTFE Hydrophobic and Ventilative Efficiency(%):99.99(with 0.3micron particles) Pore ... combine high filtration efficiency, impermeable to water, aerosols, and particlesFeatures: Hydrophobic, waterproof, windproof, ventilative, high capture particles , acid and alkali resistance ... range 0-14 Width(mm):1200-1950Thickness(micron):10-80 Hydrophobic PTFE Membrane Filter