Happy they had a size for my shoe size 10 foot. It doesn't stay on heel through the day. In morning, both feet are clinging, but by hour 8 the right foot is falling off heel and left foot is beginning to drop off heel. My left foot is a 10 and my right foot is closer to 9 1/2 that is why right falls off sooner. I am guessing the fabric is not clingy enough. They did wash and air dry well though. The silicone dots under the ball of foot are not needed and a bit annoying to feel on my foot. Normally, I would toss out these socks, but at this high price will try to live with them for a bit more. I have 2 other brands of foot socks with silicone grip at heel and they do not fall off. One brand is over ankle and only good for booties, while the other has silicone all around the sock top, that helps it to cling. I can't buy the low brand with silicone all around sock from the manufacturer because the company made them for a major shoe brand. So, I keep my eye out for them in stores and scour shopping sites in case I find them. I did see on Amazon some listings for no slip low socks with silicone all around, so those could be the sock I want, but their sizing is for small feet.