This classic, thermal base layer takes warmth and insulation to the next level, thanks to Smartwool’s innovative engineering, blending performance and functionality to give you maximum insulation and flexibility. Designed to keep you dry and warm even on the coldest of days, this slim-fitting base layer is made with 100% Merino wool fabric, which offers superior breathability, thermoregulation, and odor resistance. The fit has been updated to improve functionality and enhance aesthetics for a range of body shapes, and the back body seam wraps to the front for a body-enhancing fit. The crew neck and raglan sleeves provide a comfortable fit, and the flatlock seam construction minimizes chafing. For your next winter adventure or activity, the Smartwool Classic Thermal Merino Base Layer will be the cozy, comfortable and performance enhancing layer for skiing, hiking, climbing or biking.