Hestra Kebnekaise wool mitts are still the choice for winter sports in Scandinavia. They are simply a timeless piece of kit that work as well today as they did for the early polar explorers and Mountaineers. The wool mitts provide excellent warmth, and can be boosted when coupled with a thin liner. Adding an outer waterproof shell mitt completes the system if you need protection from cold wind and/or rain/snow. This layering principal works as well as it does for the rest of your body.
Mitts have an advantage over gloves in that they trap more air between the fingers, and are therefore warmer. On our Arctic Expedition training course last year, all the students switched to these mitts having tested them against what they brought!