Features of the Smartwool Intraknit 200 Balaclava Merino Sport yarn combines the power of Merino wool with the durability and fast dry times of polyester Engineered construction Uses knit structures to enhance Performance with lighter weights and a cleaner finish Mesh ventilation seamlessly knit in to keep the body dry and comfortable 3D Mapping results in near custom Fit and freedom of movement Fabric Details 53% Wool, 45% Polyester, 2% Elastane