First of all - the Hot Sox are great - keep your feet nice and warm quite correct. The processing looks good. Actually, almost a case for 5 star ...
But there were 3 because:
The Hot Sox are reportedly from size 36 to 40 ...
I have 38 1/2 and they fit me definitely just yet how it is. They are too short and too tight - and I have a very slender feet. In addition, the Hot Sox is also no "walking shoes" and should be of the forth quite easily.
Urgent advice therefore: rather buy the larger number!