The TRAIL Series is powered by Injinjis 5 Toe Fit System and engineered for the uneven and unpredictable terrain of trail running to offer the best fit, feel and protection inside ANY shoe. With a double elastic cuff and mesh top lock to keep dirt out and hold sock in place, youll be ready to take on the trail ahead. Constructed with: 47% CoolMax 48% Nylon 5% Lycra CoolMax in an enhanced polyester fiber and is the industry leader when it comes to moisture management. CoolMax fabric is specifically designed to provide not only superior moisture management but also to enhance the wearer's comfort. All benefits of CoolMax are built into the fiber requiring no chemical treatments like many other wicking fabrics.