Built to fit, flex, and follow you like a shadow, Smartwool's Women's Intraknit Thermal Merino Base Layer Bottom uses innovative 3D knitting technology to create the most insulated, ventilated, and flexible base layer bottoms ever. These women's wool pants feature Merino Sport yarn to offer the power of Merino paired with the durability and fast dry times of polyester — perfect for skiing, running, and all your high-intensity training.