Welcome to the new UA base system UA Base is the first line of defense any time you step into the cold. From cool mornings to the gnashing teeth of a winter squall, the UA BASE system has been completely redesignes to deliver peak performance through anything Mother Nature throws your way. A newly develpoed 4-way stretch fabric combination allows for greater comfort and mobility while the embedded moisture transport system wicks away sweat and dries quickly. UA BASE also fights the funk with premium ARMOURBLOCK anti-odor technology that inhibits growth of odor-causing microbes. In short, the best baselayer in the world just got even better.UA BASE 3.0 COLDER CONDITIONS, MODERATE TO LOW ACTIVITY. Designed to retain more warmth when external temps get severely cold.