The turtleneck offers the warmth of wool without being itchy or carrying extra weight. It is made of a blend of micro polyester and merino wool fibers. The turtleneck and thumb hole features set this men's long sleeve shirt apart from the others by making it ideal for running in cold climates. Specifically, it comes with a zip up turtleneck for extra warmth and each sleeve comes with a thumbhole to provide additional warmth for your hands.