Engineered for faster performance than ever before, the Race VECTR Sock is designed with 2XU's X:LOCK support system powered by 2XU's Compression technology for a secure, ergonomic fit to the foot and stabilization of the ankle and arch. Delivering maximum abrasion protection, extra heel and forefoot cushioning, dry mesh panels for ventilation plus a linked toe cage for comfort, the Race VECTR Sock is ideal for racing and training alike. Features: - X:LOCK support system - X:BLEND nylon fiber formula - Linked toe cage - Dry mesh panels - Cushioned heel + forefoot Size information: - S: US Women's sizes 4.5 - 6.5 - M: US Women's sizes 7 - 9.5 - L: US Women's sizes 10 - 13