We live in northeastern Idaho at 6200' where the weather is cold. The dirt roads in our rural community become slushy then freeze solid, making walking pretty iffy at best. After what traffic there is uses the roads, the ruts are glare ice. Some people here have Yaktrax, so I read about them, and watched the neighbors using them, but since the gripper parts are just coils, they do not grip very well on ice. Packed snow would be fine for the Yaktrax. Fortunately I found the Katoola MICROspikes right here on Amazon, read thru the glowing reviews and ordered them for my hubby and myself. I can say with absolute surety that these are the solution! We walk 5 miles a day with our Dalmatian (got any of these for dogs?) now we are able to walk ANYWHERE regardless of the ubiquitous ice we used to teeter around gingerly. Yes there is a bit of Achilles in the heel area, we noted that and walk accordingly, the reason being that the set of spikes for the heel is closer to the instep than to the rear of the heel. And there are no spikes in the instep area either, but that hasn't caused us any problems, but we do not run on them. One note, I wear size 8, have Maine Hunting Shoes with the insulated rubber foot, and I did order the size small, fits perfectly. But for bigger snow boots such as Sorels, the medium would be a better choice. BTW, my hubby wears size 11, has the Maine Hunting Shoes also, and the large fits perfectly as well. Thank you Katoola, and thank you reviewers! Again we have found, purchased and are happy with a great product offered on Amazon. If you have to walk on ice, get these!