I purchased the size 10 and my feet are on the narrow side. They tend to slip off if I wear ankle or low profile socks with them but don't if I wear regular socks. I guess they grip a little better. They are a little too wide for my feet and maybe a half size bigger than expected. In general they are comfortable and work for what I need them for which is wearing them around the house while doing dishes, going out into the garage or a quick trip out to the mailbox or trash can.