SmartWool Intraknit Merino 200 Crew Base Layer Top Women's NWT Pomegranate COLD WEATHER BASE LAYER. This lightweight top is made for all of your most extreme cold-weather activities. It features Merino Sport yarns and gender-specific ventilation to maximize thermoregulation and breathability during high-intensity activities. SLIM FIT. Designed to meet the demands of outdoor adventuring, this slim fit quarter zip shows off a slimming silhouette while offering unrestricted movement through the arms and chest. INTRAKNIT THERMAL MERINO. Ideal for cool to cold weather, this lightweight 3D-knit with Merino Sport yarn offers gender-specific ventillation to maximize thermoregulation and breathability during high-intensity, sweat-inducing activites. WHY MERINO WOOL? Thinner and softer than regular wool, it's easy to wear next to skin. Each fiber transports sweat away as a vapor, wicks moisture (we tested it ourselves) and regulates body temperature to keep you cool in summer and warm in win