What's next to your skin sets the stage for your comfort: don't mess around. Developed with top physiologists, Columbia's new heavyweight Baselayers offer our highest warmth-to-weight ratio for optimal comfort in extreme winter conditions. Our innovative bodymapped design keeps you warm and dry by placing Omni-Heat® reflective dots in zones that need warmth most, and Omni-Wick™ in high-perspiration zones for maximum moisture transmission. Supple fabric has a soft, sueded hand to keep it feeling (and smelling) fresh during high-exertion activities. When you start to warm up, a deep neck zipper helps you moderate heat when you need to. Highly stretchable, with flat-lock stitching to avoid chafing and raglan sleeves for extended range of motion, this is the heavyweight champion of cold-weather comfort.