I have  other Wolverine slip-ons that are size 12M which fit perfectly. These are too large. The right shoe is especially large. I thought that wearing them for a couple days would break them in so the heal would not constantly slip off my heal. It still slips way too much. I probably need a 11.5M because of the way this shoe fits. I read the return policy which is unreasonable. I could not know how badly they fit until I wore them a few time. I would like to exchange them for a size 11.5M if that is possible.