New to our innovative Intraknit(TM) line is the Men's Intraknit(TM) Thermal Merino Base Layer 1/4 Zip. This Smartwool(R) base layer is 3D-mapped for a near-custom fit and freedom of movement. Its engineered construction helps enhance your performance with a lighter weight and cleaner finish. If you're looking for base layer clothing for cold weather, this one uses Merino Sport yarn that combines the power and benefits of Merino wool with the durability and fast dry times of polyester-creating the ultimate performance-ready top for all of your high-energy activities. Design: Slim fit is intended to follow the contours of the body Featuring Intraknit(TM) technology: Insulation, articulation, and ventilation are seamlessly integrated to help with movement and comfort: Temp rating of less than 25 degrees Seamlessly knit mesh ventilation 3D mapping results in near custom fit and freedom of movement Additional Details 8.25" (21 cm) center-front zipper Made in India: 56% Merino Wool, 44% Polyester. Exclusive of Decoration