-100 degrees C. This is what the producer of the warmest boots on earth claimed. So I brought a pair with me and it only took two days on the back of a team of reindeers, the extreme cold of Yakutia and a high speed for me to realize, this was just hogwash. Before the journey, see pitcure, Egor got his friends in Androskhkino to make a full set of fur clothes for me, thugh they were tundra people, not taiga people, they weren´t perfect on the trip, but way better than any modern clothes. My fur boots, too short for the deep snow in the taiga, was stuffed with dry grass, an additional fur boot put inside, with the hairs out, no socks and they worked wonders! Best of the best and I stopped freezing the worst of my butt off. This time with the Eveny reindeers herders, who i would call the last true survivalist people, and as close as you can, closest living with the true elements of nature, they taught me a lot. However, once I got a bit warmer, they were way too hot (we are talking around -30 degrees C, and I started to wear the lighter and more flexible modern gear again from Mountain Hardwear. The documentary from this epic journey, winner of the Golden Goggles, can be seen at the Siła Marzeń – Festiwal Przygody (Adventure festival) in Warsaw 26th of May 18.20-19.35 http://www.festiwalsilymarzen.com/ . If you want to read the blog reports from the adventure, see https://www.mikaelstrandberg.com/?s=frozen+frontier