The Thermo kNight™ AA battery powered Vest is made from plain-weave stretchable fabric which offers 4-way stretch comfort, breathability and light wind protection. Increases your core body temperature to keep you warm even in the coldest of climates, it also provides modest water repellent finish to resist moderate rain and wind. The construction makes it warm, light and ideal for all-purpose outerwear, and sleek enough to layer. Heating system features comfort control allowing you to utilizing the heating area to be used intermittently as you need. All Thermo kNight™ clothing features the revolutionary heating technology to enable you to create your own personal micro-climate because nothing should come between you and your adventure - not even Mother Nature.