Great socks but they run a little on the small size. If you're between sizes or not sure which size to get—then go for a size larger just to be safe. The extra-large fit my size 12 feet.
Too thick and wooly feeling for me. They seem like a quality sock and even though I like to wear warm socks around the house in the winter, I did not like the feel of the socks on my feet. They most certainly would be warm outdoors but the shoe or boot would need to be large on your foot to accomodate these socks. I am returning them.
I wear a women's shoe 8 to 8.5 and, after reading the more recent reviews, decided to order the unisex L--one size up from the M I last purchased, six or eight years ago. The L just fits without having to stretch. 8.5" from toe to heel 'seam', 8.75" from heel to top of cuff (not the 10" given in the description). Perhaps these are supplied from several different contractors, who aren't consistent in their manufacturing?
Silk or cotton liner socks are a good idea with these if you're sensitive to wool--for some people, there is just no such thing as an itch-free merino. However, it's warmer and more breathable than any synthetic I've ever tried, so these socks are a staple both in winter and in summer air-conditioning.
I LOVE these socks! They keep my tootsies warm, they stay fitted, and they are so thick. I am a size 8 in women's and ordered a Medium. They fit perfect, with still a little room, but not too big.