I have tried the regular Klim socks (25 pr) and the Klim Mammoth socks (33 pr). I prefer the regular ones. The Mammoth are very thick and make my boots too tight. The regular ones seem "just right" for warmth without sweating. I have never had a problem from -10 to 30F. Ended up getting another pair of the regular ones, and never wear the Mammoths.
