Run Low Quarter

Great performance and good value
Predictably live up to their reputation and claimes of the finest socks for all feet
And the service online is excellent

I wear 10-10.5 shoe sizes and bought eco double layer run bar 0 75508 16340 3 that has a little pull tab above the heel, and slide off my feet.
The company replaced with same bar code 0 75508 16559 9 in white and replaced that with a black 0 75508 16521 6 both of these have flatter top of the sock that also slide off my heel, in fact to the middle of the heel
I have since cinched the shoe strings a little bit better over the top of teh foot, and that helps some These are all Large, and it was determined the xl would be too big

I have known about these socks for years, and the best part was is their term" 2 sock performance, 1 sock feet) .
The inner white sock (like old term coolmax) is a benefit to prevent blisters, and helps AVOID blisters, and that is a big plus)

they launder well, and need turned inside out, and by tightening the shoe strings , they work better

my only criticism is they need to have a better way to stay above the ankle without being too tight and make impressions in the skin.

It may be my shoe or foot,
But, they are good quality

I prefer black because in all white socks I have, sweat discolors the fabric that is a dirty brown. So far in washing in a front loader in a laundry back, they have not faded.