The Terramar Men's Thermolator Baselayer Crew Base Layer Top is where form perfectly meets function. The midweight fabric is ultra-soft and features ClimaSense Thermoregulation Technology that automatically adjusts to your body temperature. When you are cool it traps air to maintain warmth. When aerobic activity rises and the surface temperature increases the fabric allows moisture vapor to escape to maintain comfort. Whether skiing or mountaineering, Thermolator is the functional performance essential you need for all your adventures!