The Smartwool has taken their Intraknit material and added a knit-in wind protection to the front panel and sleeves as well as a DWR finish so this mid-layer piece can go with you on any outdoor adventure. Hike in it, ski in it, go running, targeted mesh ventilation zones have your back if you start to work up a sweat. It's soft and stretchy and moves with ease. The perfect addition to your layering system.