The material is 100% mulesing-free merino wool of the highest quality, which feels comfortable with its optimal temperature regulation - keeping you warm when it`s cold and cool when it`s hot. Merino wool is self-cleaning and does not absorb sweat odor. And it can absorb up to 35% of its own weight in liquid without feeling wet. Also, check out the lighter Men`s Merino 150 LS shirt.