Patagonia&';s most versatile baselayer wicks sweat and provides balanced warmth in a wide range of winter conditions. It&';s smooth for easy layering, stretchy and soft next to skin for all-day comfort, and keeps you warm in cool to cold conditions. Made in a Fair Trade Certified(TM) factory. Versatile Across a Wide Range of Conditions High-bulk, low-weight yarn and double-knit construction produce a high warmth-to-weight ratio with breathable, sweat-wicking performance across the widest range of temperatures and conditions; with a smooth face for easy layering Low-Bulk Zip-Neck Low-bulk zip-neck offers easy venting, with internal neck tape that boosts comfort and a locker loop for hang drying Raglan Sleeve Construction Raglan shoulder seams and full underarm gussets minimize chafing and allow total freedom of movement Low-Profile Thumb Loops Thumb loops made from the body fabric provide secure hand coverage; minimal branding at the left-front hem Minimal Seaming Minimal, low-bulk seams reduce chafing and increase comfort over extended wear Fitted for Optimal Wicking Fits next to skin without being compressive for optimal wicking, easy layering and freedom of movement