Made to to respond to active, transition and recovery needs, the 2XU Performance Compression Run Sock is designed with graduated construction, ergonomic cuts and world-leading compression fabrics. The calf and shin support improves circulation, reducing muscle fatigue and protecting you from the possibility of blood clots. The sock also has moisture management to wick away sweat and keep your foot dry. Men's Sizing: shoe size 6-8.5 (S); 8-10.5 (M); 10-12.5 (L); 12-14 (XL). Women's Sizing: shoe size 5.5-8 (XS); 7.5-10 (S); 9.5-12 (M); 11-14 (L). 72% nylon/28% spandex. Imported.