If you crave that running outdoor adrenaline in the middle of winter, then slip into the Yaktrax(R) Run traction device. Designed for the extreme runner, this ice traction accessory fits right over your athletic shoe, allowing you to keep your workout going on snow and ice. SIZE CHART: Small (S): Women's 6.5 - 10 / Men's 5 - 8.5 Medium (M): Women's 10.5 - 12.5 / Men's 9 - 11 Large (L): Women's 13.5 - 15 / Men's 11.5 - 13.5 Extra Large (XL): Women's 15.5+ / Men's 14+ DESIGN: Designed to fit over running shoes and provide anatomical fit with left and right design Made of high strength natural rubber for flexibility Reflective heel tab and performance strap helps to keep you safe during outdoor runs DURABILITY & TRACTION: 1.4mm steel coils and steel spikes for traction and durability Carbide steel spikes ADDITIONAL DETAILS: Can be worn in extremely cold temperatures down to -41degF Weight: 9.7 - 11.7 oz per pair