The Cloud Nine Tight is the ideal baselayer and thermal long johns for all day warmth and comfort while being out in the elements. This versatile piece features an ultra-soft, midweight fabric utilizing our features ClimaSense Thermoregulation Technology that automatically adjusts to your body temperature. It does this by trapping air to maintain warmth when your body starts to cool down. When your aerobic activity increases and your skin temperature rises, the fabric allows moisture vapor to escape to maintain comfort.