The secret of theThermawool is blending merino wool with just the right number of microfibers to make the ideal technical thermal fabric to breathe and manage moisture. Thermawool has the benefits of Merino Wool with a soft fleece against your skin. TheThermawool Pant is ideal for a layering piece or on its own. It works great on its own or with the Thermawool Crew or Half Zip.