The Smartwool Intraknit Thermal Merino Base Layer Men’s Colorblock Crew blends style and performance into one, designed with a colorblock patterning for a unique look and 3D mapping, custom fit. This slim-fitting base layer is made from a 53% Merino wool, 44% polyester, and 3% elastane blend that is designed to provide maximum warmth and comfort. Boasting a custom fit, you achieve a wide range of motion while enhanced durability features such as the ribbed elbows make this shirt last season after season. The mesh ventilation zones are seamlessly knit into the garment to keep your body dry and comfortable while remaining highly breathable. Whether you're hitting the slopes or just taking a walk in the cold, this base layer will keep you cozy all winter long.