UA Base 3.0 is built for very cold weather and moderate activity. It uses a unique pattern that's designed to trap heat without adding bulk. Think long underwear, revamped for today's top athletes.

UA Base™ 3.0 All Season Baselayer provides midweight warmth at many activity levels & cold temperatures
UA Scent Control Technology to keep you undetected in all pursuits
Soft, brushed grid interior traps air, managing your body's microclimate to keep you warm & comfortable
Material wicks sweat & dries really fast
4-way stretch construction moves better in every direction