Made from wind-resistant nylon， the STIHL Function Winter Shirt helps you forget about the elements so you can focus on the task at hand. Inside， a layer of breathable Thinsulate retains body heat， while allowing water vapor， such as sweat， to escape. It also features two breast pockets for convenient storage and a stand-up collar for keeping out rain and snow. On the back of the shirt， the yoke is vented， improving overall air circulation.