The membrane we use in STORM’s products is called W3, which is a micro porous membrane. Compared to other generations of wind and waterproof materials, it is half as thick and offers constant and extreme high breathability. And this is irrespective of climate or intensity of any activity.
The membrane helps to keep your body dry while maximizing the isolation capabilities of other clothing. ECWF (Extreme Cold Weather Fabric) is a standard test used by the US Army. Only a few membrane manufacturers can stand up to this test and be approved.
W3 is one of the few and is on top in several tests.