A breathable fabric allows the perspiration produced by physical activity to pass through it. The breathable nature of the fabric promotes biological breathability which allows body moisture to be expelled easily, thereby decreasing condensation from perspiration, increasing comfort. A breathable fabric measures the water vapor, expressed in grams, that crosses an area of 1 square meter in 24 hours (g/m2-day).
By windproof we mean that the fabric cannot be penetrated by strong winds. The windproof feature helps to maintain body heat, prevent sudden changes in temperature and increase comfort.