This T3 Women"s Light Trail Running Sock features 3 separate layers of fibers that work together for comfort, support, and moisture management. A layer of TENCEL® provides a layer that is soft to the touch and comfortable against the skin. It is a fully biodegradable fiber that is made from trees from sustainable farms. The COOLMAX® layer works to move perspiration away from the body, and through the fabric, where it can evaporate quickly, allowing the wearer to feel cooler and more comfortable. Lastly, a layer of Nylon and Ea. LYCRA® adds durability and ensure these socks stay up in your running shoes without slipping down to your toes. These 3 Layers make the T3 Women"s Light Trail Running Sock perfect for running in any season. Your feet will stay dry and comfortable all day long.