What’s it do?
UA Base 4.0 is built for extreme cold weather and lower activity. Their unique pattern traps heat without adding bulk. Think long underwear, revamped for today’s top athletes.

DNA
UA Base 4.0 Extreme Baselayer is our warmest yet, delivering extreme warmth in the extreme cold
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
Dropped, shaped hem
Raglan sleeve