By blending Coolmax and Thermolite into their CS100 fabric, Craft designed the Women's Active Extreme Long Sleeve Crew to keep you dry 100% of the time. The elastic fabric stays in contact with your body, pulling excess moisture away from your skin while simultaneously keeping you warm. The outer layer allows air to circulate around your body, enhancing moisture expulsion. Thin, lightweight, and extremely elastic fits under jersey perfectly. Ideal for cold to fair conditions (30-65°F.) XS-XL.