What Our Gearhead® Experts Are Saying:“This is one of my go-to midweight base layers for winter sports. The ClimaSense fabric keeps me warm on the lift, but breathes when I’m working hard—plus, it’s soft enough to wear all day without irritation.”From brisk morning chairlifts to high-output climbs, the Thermolator 2. 0 1/2-Zip Top adapts to your body’s needs with ClimaSense thermoregulation technology. When you’re cooling down, the brushed interior traps warm air to keep your core comfortable. When your activity heats up, the breathable fabric releases excess heat and moisture vapor so you don’t overheat. The midweight build offers versatile warmth for a variety of winter pursuits—whether that’s skiing, mountaineering, or a cold-weather trail run. Four-way stretch ensures unrestricted movement, functional thumbholes keep sleeves in place, and mesh panels boost breathability where you need it most. With UPF 25+ sun protection and odor control, it’s a reliable layer for multi-day adventures and bluebird days alike.