The Merino Core [MC] collection utilizes an extra-fine 18.9 micron 190g/sm Australian Merino Wool which is spun around a core of nylon for strength and durability. By its nature, Merino Wool is a highly technical performance fabric. It is breathable, has stretch, resists odors and naturally wicks perspiration away from the body to keep you warm in cold weather and cool during exertion or as the temperatures rise. What makes this fabric truly special, however, is the addition of a fully encapsulated nylon filament in each yarn resulting in a textile that is also incredibly strong and durable.