New to Smartwool's innovative Intraknit™ line is the Intraknit™ Thermal Merino 1/4 Zip Base Layer Top. This Smartwool® 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.

• Slim fit is intended to follow the contours of the body
• Featuring Intraknit™ technology: Insulation, articulation and ventilation are seamlessly integrated to amplify movement and comfort during high-intensity activities
• Merino Sport yarn combines the power of Merino with the durability and fast dry times of polyester
• Seamlessly knit mesh ventilation designed to keep you dry and comfortable
• 3D mapping provides maximum mobility while ribbed elbows provide added durability
• 8.25" (21 cm) center-front zipper