Yaktrax Run Traction Cleats were designed by runners to permit users to continue running and training in winter. Run Traction Cleats attach over running shoes with a high-strength rubber foot frame that includes straps over the toe in addition to excessive of the foot for additional security; the heal and side straps of the frame feature reflective material for safety. Yaktrax Run Cleats offer superior traction way to replaceable, 3mm carbide-steel spikes combined with a shaped-edge coil design of 1.4mm rust-resistant stainless steel coils so users can run with confidence on packed snow or ice. More than one coil angles provide 360 degrees of traction on cold surfaces for stability in all directions. Yaktrax Run Traction Cleats have been tested in temperatures as little as -41 degrees Fahrenheit so they are able to be utilized in a lot of extreme environments. Yaktrax Run Traction Cleats come in four sizes to suit most shoes: Small (fits shoe size W6.5-10, M5-8.5); Medium (fits shoe size W10.5-12.5, M9-11); Large (fits shoe size W13-15, M11.5-13.5); X-Larger (fits shoe size W15.5+, M 14+). For oversized shoes or boots, Yaktrax recommends purchasing one size larger than your normal shoe size.