I purchased 10" length and 12" length. I found the 12" length is perfect for me. I would not recommend the 10" if you use them for work. I work outside in the snow and cold weather. They covered the thermal underwear with no problem. However, the 10" gave me a problem of not covering the thermals well. My feet were warm. I am very much satisfied.
I ordered these socks to wear at night when I sleep. Yes, they do keep my feet warm. But, I have to say I am greatly disappointed in the quality of construction of these socks. The toes are simply sewn with a flat seam at the end of the sock. The sign of a quality sock is one that has no detectable and annoying bulky toe seam. You have to constantly arrange the sock so the seam does not get in the way. If the toe was actually woven into the sock and not just cut and sewn in the crude manner that these are sewn they would be excellent socks. I would not order these again or recommend them to anyone. I especially would not recommend them to anyone who does not just wear these to bed. To put a shoe over a bulky uncomfortable thick toe seam would be just asking for major foot/shoe discomfort.
I'm a confessed sock nut. I love a good pair of feet warmers. I purchased 6 pair of these three winters ago. They have been through every kind of storm and weather here in New England - I do a lot of hiking. They have been washed dozens of times and you know what - they still look and feel great. Hardly any piling. Good color retention.
Just a side note, I wash them inside out and let them air dry. One should really do that with all socks - if you want them to last.
