I had earlier in some socks the problem that the feet after 5-6 km began to go numb (also fitted with a custom running shoes did not think much longer). I have worn the Hawk Running Socks now frequently while running. And it has really brought something. Numbness and pain are passé. It's a very good feeling that even after 1.5 h (and perhaps longer, I normally do not run) feet still "join", are painless and mobile. The Falcon running sock for me is a must have.