The SmartWool Running Headband is made from 100% Merino Wool, a highly durable, comfortable and versatile fabric. The wool is naturally moisture and dirt repellent due to the structure of the wools fibre properties, and the presence of keratin in the wool not only gives it great elasticity and strength, it is also responsible for the wool being a natural water repellent. The headband is reversible and simple in its design, to offer you great protection, comfort and versatility.