From SmartWool, this T-shirt features: Colorblock design Regular fit Crew neckline Long sleeves Intraknit™ technology: insulation, articulation, and ventilation are seamlessly integrated to help with movement  and comfort during high-intensity activities Body-mapped knit structure that helps with insulation Seamlessly knit mesh ventilation Merino wool/polyester/nylon/elastane Machine wash/tumble dry Imported.