Wicking sweat in summer helps keep you cooler, however, in winter it's all about keeping your skin warm and dry. Assos' Ultraz Winter Long-Sleeve Skin-Layer works in tandem with your outer layers to wick sweat away from your body to avoid becoming saturated and cold when cycling in winter months. The seamless construction ensures next-to-skin comfort by eliminating seam lines and weight. Assos uses medium-weight yarn to supply the insulation you need, but not so much that you'll feel stuffy when hitting climbs or harder training sessions. And carbon fiber threads are integrated to add durability to this soft baselayer.