Built-in Climate Control If go-to versatility is what you seek, the men's Burton Midweight Base Layer crew balances warmth, breathability, and quick-drying performance with built-in climate control that you can count on all season. Features: Midweight 200 reacts to your body temperature, accelerating moisture wicking when you're hot and retaining warmth when you're cold for balanced comfort all day long Small Details Make a Big Difference Stuff like thumbhole cuffs and chafe-free seams up the comfort factor. Stink Less. The sustainable odor control of HeiQ Fresh keeps it fresh without limiting breathability. Low Environmental Impact Bluesign® approved materials reduce impact on humans and the planet during manufacturing.