The Smartwool Classic Thermal Merino Base Layer 1/4 Zip - Women's is a Merino wool base layer for cold-weather comfort. When the skiing, hiking, and winter-weather activities must go on, treat yourself to 100% Merino wool. It naturally wicks sweat away from the skin, regulates temperature, and resists odors, so you stay comfortable and warm during physical activity. It features a quarter-length zip to ease on and off and adjust internal temps quickly.