Kahtoola MICROspikes® Traction System allows anyone to get out and enjoy most any condition. Since there are no special straps, you simply put your Kahtoola MICROspikes® in your pocket, purse or backpack and go. Take them out and stretch them over your shoes when you need extra grip - they're ideal for anything from wet rocks to slick sidewalks and icy driveways, or even the added confidence that comes along with extra traction on the trail. Add the MICROspikes® to your gear and get out there! Size based on shoe size. Small (mens 5-8, womens 6-9, oversized pacboot 5-7); Medium (mens 8-11, womens 9-12, oversized pacboot 7-9); Large (mens 11-14, oversized pacboot 9-11); X-Large (mens 14-16, oversized pacboot 11-14)