Slim Fit Engineered construction uses knit structures to enhance performance with lighter weights and cleaner finish Merino Sport yarn combines the power of Merino with the durability and fast dry times of polyester Garment Weight: 180 g = 6.35 oz Knit in India: 53% Merino Wool, 45% Polyester, 2% Elastane 3D mapping results in near custom fit and freedom of movement while ribbed elbows provide added durability Mesh ventilation seamlessly knit in gender-specific zones designed to keep the body dry and comfortable