Really, really love these socks. They are some of the warmest we have ever worn and we have gone through the top of the line wool socks from Cabelas, Bass Pro, Carhartt, etc.. These heat holders are fantastic. They feel really think and bulky when you put them on but seem to flatten somewhat when you put shoes on. Not in a bad way, it is actually a good thing when putting on boots. Bought me a pair, then my wife and daughter wanted some so we had to get everyone a pair. Bough the extra long for my wife as she wears boots and skirts and these are fantastic.