What Our Gearhead(R) Experts Are Saying:"I wore this on a trail run that started cold and warmed up fast, and it kept pace with every temperature swing. The four-way stretch never bunched under my pack straps, and the hidden thumbholes kept my sleeves in place mile after mile."A dawn start on a ski tour asks a lot of a single layer, cold and still at the trailhead, working hard on the climb, exposed to wind at the summit. The Clima-Tek Hoodie from Hot Chillys is built to keep up with all of it, soft spun polyester that moves with every stride, relaxed enough to layer under a shell on the way up, and comfortable enough to wear alone once the sun takes over. Activated carbon woven into the fabric manages both heat and odor as exertion increases, while moisture transfer fibers keep skin dry through sustained effort. Hidden thumbhole loops secure sleeves through repetitive movement, and UPF 30 protection covers exposed skin once the light breaks through, making this a hoodie built for the whole day, from first skin track to last run down.