Love these socks they never slid off because of this sticky part on the heel inside the sock. I am a size 10.5 and with wearing them all day they leave a ring around the top if my foot as if it's pressed too tight on top of the foot...but is somewhat stretchy so fits perfect.  I've had these for 3 months and I can truly say they fit perfect now.  Made of good quality,  hasn't ripped I am buying more soon. The strips make it easy when after washing clothes I know who's socks are who's.