I purchased these for use on my mountain bike bike shoes. I prefer these shoes for both my commuting and mountain biking needs since they are nicer to wear around after the ride when needed. That aid, I was hoping that these covers would suit my needs, after the initially too small of a size, they do.
My main frustration with this product is that the sizes do not seem to be listed. They are listed as small, medium, etc., this doesn't work for me. So I took a chance and ordered the X-Large ones hoping that they would not be too big/small, they ended up being way too small. When I got them there are shoe sizes listed in each one, a feature that would be great on the sellers site. To give you an idea, the size that I ended up with after returning the too small version as the XX-L version. Here is a size chart I ended up finding on the product:
S M L XL XXL
Shoe Size 7 7-8.5 8.5-10 10-13 13-15
Shoe Size(Eur) 0"-39" 39.5"-42" 42.5"-44" 44.5"-46" 46.5"-49"
If you plan to use these covers on pure road bike shoes the sizing chart should be right on for you. I you want to use them on a pair of mountain bike shoes, I would recommend the next size up. I wear 11's, and the XL was way too small for them.
Apart from the sizing issues, this product is very easy to put on and use, and works as you would expect. It blocks the wind, and most of the water, just not the water from a torrential downpour, which I did not expect it to do anyways.
Great product once you get fitted!