AIRMEM COLORSHELL, By using millions of micropores in the material to let the moisture passes through the pores directly. AIRMEM™ microporous membrane features water resistance is based on the aperture of the pores controlled between 0.2-10μm. It can prevent raindrops (size of 100-3000μm) permeate from outside and allow humid vapor(0.0004μm) diffuse from human body. This unique structure provides air exchange and moisture dissipate while remaining completely dry.