These boys thermal underwear set include one thermal compression pant and one thermal shirt, they use ultra-soft & smooth fabric for extreme comfort with very little weight. It has a soft fleecy interior that helps hold in heat. Slim, stretchy design let you move free and easy or layer for warmth, and material wicks sweat & dries really fast. Extremely simple design -using less seams to reduce irritation from chafing in activities. Anti-odor technology prevents the growth of odor, keep you stay comfortable and focus. These boys fleece thermal compression pants as perfect sports base layers. Improve your performance for skiing, snowing, soccer, basketball, hockey, baseball, lacrosse, jiu-jitsu, snowboarding and other sports in cold weather days.