I put on a 37 and this is perfect for the amount boots to the knee. The downside: the upper hook is not very strong and yielded to the first fall (we could repair damage but we see that this is just clipped) and does not really allow for hanging boot
Currently I'm using these for a pair of boots (size 37 women's). They sccm to do the job well, it just takes a little practice to put 'em in since you-have to keep squeezing the sides up to you-have boot the trees all the way in. I have to open the s