How Fortress Works
Fortress is a “base” or “mid-layer” cold weather garment that is designed to keep you warm - even when wet. It is designed also to be worn as a mid-layer garment (ie: underwear/Fortress mid-layer garment/outer shell appropriate for the conditions –typically NOT an insulated coat).
The non-technical description:
Water (sweat) is WHY you get cold. Fortress doesn’t hold on to water, or the perspiration your body puts out. Through the laws of physics, it moves it (pushes away) from your body to the outside air to keep you dry and warm. Other insulation materials (don’t breath) and hold on to your perspiration, it builds up, adding a layer of moisture against you- which decreases your ability to stay warm. (Water is 25X more conductive than air) Our insulation material (Aeris Inside) does not allow moisture to build up. In fact, it repels it.
Then, we use an outer material that is windproof, but not waterproof. Some other clothing in this category claims a "waterproof/breathable" feature. This can be misleading because such fabrics can be overwhelmed. These garments are typically 100% Waterproof and only 15% breathable. Once overwhelmed, they start to develop a “build-up of moisture” which causes you to get cold. Our clothing does not do this. Fortress clothing ROCKS! Staying warm through a wide comfort temperature range, unlike other garments that get uncomfortable outside of their narrow comfort range. Depending on the build of your body, metabolism, hydration and activity level… Fortress has been worn from -30°F to 70°F !! Go figure!