Warm and comfortable Merino Wool - You'll want to keep it on forever, Ornot. You know that favorite piece of clothing? The one you always wish was clean? This is it. Our Power Wool Thermal Jersey offers the finest balance of comfort, breathability, and insulation. Cut from Polartec Power Wool, our jersey features a soft, extra-fine merino interior and a moisture-wicking, quick-drying, abrasion-resistant Nylon / Polyester exterior.