CFM Is a Measure of Fabric Breathability

Cubic feet per square meter is a measurement of how much air breathability and air resistance a fabric has. A higher CFM is more breathable, but less wind resistant and a lower CFM is less breathable and more air resistant. For example, a fleece typically has a very high CFM (200+), but usually does not block the wind. Similarly a windbreaker has a low CFM (3-5), but can feel like wearing a garbage bag under high exertion.

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