Polartec Power Stretch is highly breathable and does not restrict the movement of moisture vapour. "Touch Points" on the fabric inner surface draw off the sweat. Sweat is wicked off the skin to the outside of the fabric, where it spreads rapidly for evaporation. When the sweat reaches the outside of the fabric, it spreads out to many times its original surface area, enabling it to dry at least 2 times faster than cotton. The 4-way stretch of the fabric provides unrestricted freedom of movement and provides warmth without the weight and bulk of traditional insulating fabrics. It is also wind resistant to reduce the effects of wind chill and machine washable.