Why invest in a quality base layer? So you don't have to think about it again. If you've ever been stuck in damp cotton underwear in chilly weather, you know how uncomfortable an experience it can be. Damp cotton will transfer your body heat 20 times faster than dry fabric! With these lightweight, close-fitting thermal pieces, you'll never be cold and clammy. High-tech base layers wick away moisture, dry quickly, and trap warmth next to your body.