The Grip6 socks feel well made, and are no doubt high quality socks. Unfortunately the heel material is quite thick such that my feet slide all over inside the shoes. So I am unable to use them. These are New Balance shoes that I've been wearing for a decade while wearing Red Wing diabetic socks where my feet don't slide around at all with those socks. So I guess I'll just buy some more Red Wing socks. My feet are size 10. I ordered X large Grip6 and they are VERY tight on my feet, almost to the point of discomfort. (yep... wide feet) I felt instant relief when removing them. I don't have that problem at all with size 12 Red Wing diabetic socks. (Not a commercial for Red Wing, just offering a comparative experience) Definitely NOT being critical of the Grip6 socks which are clearly high quality. They just don't work well for me.