Under Armour's base layers are suited for different climates, with their HeatGear (for when it's hot), ColdGear (for when it's cold), and AllSeasonGear (for when it's hot or cold!). Of course, we are mostly interested in their ColdGear products since it's usually a requirement for it to be cold in order for there to be snow for us to all ski on. These Under Armour base layers are meant to fit tight and are meant to stretch in order to provide a perfect, technical fit which ensures maximum moisture wicking and warmth.
Even some of Under Armour's outerwear offerings feature similar features to their base layers. The Unchained jacket features ArmourStretch fabric and strategic placement of ArmourLoft Insulation, both of which allow the wearer to move freely without much restriction. In addition to these two features, the Unchained is considered part of Under Armour's ColdGear line, which are designed to keep you warm by wicking moisture away from the skin while circulating your body temperature.