How does a waterproof and breathable valve achieve waterproof and breathable properties?

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Your answer can be found online; just remove the name of your company from it. A waterproof and breathable valve uses expanded polytetrafluoroethylene as its breathable membrane, which has a microporous structure at the microscopic level. By taking advantage of the difference in size and quantity between gas molecules and liquid droplets as well as dust particles, gas molecules can pass through, while liquids and dust cannot, thereby achieving the purpose of being waterproof and breathable. Water is generated because, during operation, the product draws in water vapor under negative pressure; when this vapor condenses inside the inner shell, water appears. After installing the waterproof and breathable valve, air is filtered through the PUW waterproof and breathable membrane under negative pressure; the air drawn in contains tiny amounts of water vapor. Even under positive pressure, this vapor can be expelled, thereby achieving a balanced pressure difference between the inside and outside, allowing for breathability while also preventing water from forming.