The Kari Traa Olea Half Zip is a baselayer top made from lightweight 100% merino wool, a close-fitting layer that keeps warmth against the skin on cold days. A Nordic pattern sets the top apart from a plain baselayer. What Our Gearhead(R) Experts Are Saying:"I keep the zip up on the chairlift and drop it a few inches once I'm climbing, so I never have to strip a layer to cool off."