These "are what they are" - inexpensive light duty easy to carry compact temporary shoe covers for occasional and relatively brief use. Buy them and use them for their intended purpose, not for bicycle riding, etc. Great for what I wanted: to get through snow from airport to car and car to destination, for those times there's several inches of snow but I don't want to haul boots around with me, since I travel for work all the time and don't check luggage. The soles are flat, so these work great with my "running" shoes that I wear most of the time. The plastic uppers are waterproof, and therefore they don't "breathe," so not great for prolonged were in wet/humid environments. The uppers are also relatively light weight material, so these are not designed for long distance walking or hiking. Fit is important for normal walking and to keep the uppers from working their way underfoot, where they surely wouldn't last long. I got XL, good fit with my size 11 shoes. 11.5 would probably fit, but I doubt size 12 shoes would. I bought a second pair, for another location.

If you wear Size 9-11 shoe, you need Size LARGE and not Medium like the product states. Quality of the product is pretty low, these are cheap and won't be lasting for very long methinks.

Some people say that the products they buy are too small, I guess they should not understand the size chart on the picture.
The size of the article refers to the size of the product, not the size of your shoes. When you buy, choose a size bigger than your shoes.
Before I bought it, I looked carefully at the size chart in the picture. It's just right.
Got a pair for me and my wife for motorcycle trips. We got to try them out in a rain storm recently and they worked great. They kept my boots dry which kept my toes dry.
I'm extremely happy with this purchase.

Work fine but have the durability of tin foil. Used on trine bicycle and the pedals tore through the soles on first lap around the block. Also condensation was so bad that there was no point in using them.

My elevator pits flooded and I had to send my cleaning contractor down there to vacuum out the water. I was pleasantly surprised that this shoe covers really worked and kept his shoes dry while standing in 6 inches of water.