Smartwool&';s Men&';s Classic Thermal Merino Base Layer Colorblock Crew features 100% Merino wool made with a flatlock seam construction and offset shoulder and side seams designed for enhanced comfort, breathability, thermoregulation, and odor resistance. From hiking to running and skiing, this base layer brings consistent comfort, plus reliable warmth and durability, for every winter activity.Specs Origin: Vietnam Material: 100% Merino Wool