What's it do? 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 material moves better in every direction Wide, flat waistband with a rise that sits just right on your hips Questions? Leave a comment below!