With a lightweight, water repellent, cutting-edge design, the Shefford Vest with Powerbank delivers technologically innovative comfort and warmth like nothing else in our menswear line. The included UL Listed Cycle 6000 mAh Powerbank (7121-62) controls the temperature of the vest by powering interior heat panels at the chest and back, providing up to 2.5 hours of warmth at the maximum setting. The Shefford has three temperature settings that can be easily controlled at the touch of a button: Blue = Low (100°F), White = Medium (113°F), and Red = High (131°F). Please note that the included power bank will be shipped blank. For a decorated option, the powerbank and vest must be purchased separately. The men's version of the Shefford Vest is made from durable nylon and polyester with a cozy faux down filling.