ePTFE porous membrane for air filter. Spacerate is about 82%, average hole diameter is about 0.3um. The membrane hasspecial functions of high breathability excellent chemistry stability, smallfriction quotiety high temperature resistance etc. After laminated with the99.99%. It’s the best choice for any kind of high efficiency particulate airfilter.Because the PTFE membrane has a structureof multi-holes, and the diameter of the hole is much bigger than water vaporand much smaller than a water drop. The PTFE membrane has a character ofextremely. It’s the optimum solution for who need to face extreme weather andtough conditions after be laminated with special fabrics. Such as firefighter,enthusiasts, etc.