Warmest mitts I've ever owned. Throw them on and my hands are sweating after 15 min. The shells are amazing, I've put the shells on top of my gloves during a 90 minute skijor and my hands actually got too warm in 15 degree weather. Not to mention the leather grips very well. The liners are great as well, very warm just on their own. I always bring these any time I'm ice climbing or doing any sort of Alpine movement. Can't recommend them enough. The leather mitt is a vast improvement over the synthetic alti glove.