Austin Saariwrote a review of Mammut Mamook Thermo Boot - Men's on April 17, 2013
First time I ever wore these boots I got blisters on my heels the size of golf balls. However the boots were very comfortable and I did not want to give up on them. I went home adjusted my lacing technique and taped my feet. In over 100+ miles of colorado 14ers I have not got one blister or sore spot. I do 15 mile days in these boots no problem. And they still look new! Switch from spikes, crampons, snowshoes no problem. I normally have really cold hands and feet because of bad circulation so As for the warmth of these boots I've been in 5-10F weather with only a REI light hiking sock and been warm enough, the key is to keep moving!
I was told these boots are a 2 piece boot, however there are just 1 with a removable sole!