Seirus’ HeatWave+ liner technology is just plain bonkers. First, a kinetic fabric increases temperatures by four to five degrees when you’re in motion. Second, a reflective printed coating radiates warmth back to your hands. Third, a proprietary layer converts your emitted energy into heat. Don’t get bogged down by the science… Just know that all that, plus 300 grams of synthetic insulation, is enough to withstand the most frigid, teeth- chattering days on the hill.