The Columbia Midweight Stretch Baselayer Long Sleeve Shirt - Women's is a stretch baselayer for comfort during cold adventures. The fabric is a polyester and elastane blend featuring Omni-Heat Reflective and Omni-Wick Anytime, which reflects body heat for more warmth, wicks moisture, and dries fast. The combination allows you to physically push yourself whether hiking, skiing, mountaineering, or some other adventure on cold days of the great outdoors.