Brynje Arctic Extreme is suitable for many different activities from full expedition use to general outdoor activities. Arctic underwear is particularily suitable for high output activities where there is the potential for a dangerous chill factor when resting. The combination of Super Thermo net and Merino wool produces a garment with excellent ventilation and moisture transport capabilities. The Meraklon Super Thermo net fabric is brushed to increase insulation and comfort against the skin. As the body heats up during activity the Meraklon net allows moisture to escape readily from the body to the next layer of *Merino wool. The Merino wool readily transports the moisture to the outside surface where it can evaporate. In addition to transporting the moisture both the Meraklon net and Merino wool provide insulation. The cells in the Meraklon net fabric maintain a warm cushion of air next to the skin while the Merino wool provides an additional, natural, insulating layer. The result of these two layers is a remarkable combination of warmth and dryness in one light weight garment. Arctic Extreme underwear is worn next to the skin serving as a single integrated layering system. For complete protection from the elements a waterproof/windproof shell or insulating jacket can be worn as an outer layer. The feedback from numerous expeditions from the North and South Poles to Mount Everest is that Brynje Arctic Extreme underwear offers exceptional performance. No other single garment offers the unique combination of warmth and light weight while maintaining the technical demands of moisture transfer and ventilation. Arctic Extreme garments are essential outdoor equipment. *Please note that the Brynje Merino wool is now blended with 30% polyester to which increases the durability of the wool. This blend also makes the Arctic underwear very easy to launder.