I bought my first pair of these socks on clearance at my local R.E.I.; however, I'm now addicted and since I no longer live near an R.E.I. I have to get them on Amazon.  I have a tiny foot, shoe size 6, and so regular women's socks that come 'for shoe size 6-10' always stretch out and are ultimately too big but if I buy socks in the girls section I can't find any with extra padding around the ball of the foot and heel, which I desperately need....these socks actually come in an x-small which fits me perfectly.  They are very comfortable and do not slip around on my feet like most socks do.  I will certainly continue to buy more as these wear out.