The Men's Shefford Heat Panel Vest with 6,000 mAh Power Bank delivers comfort and warmth like nothing else in our line. The Shefford features lightweight, water-repellent warmth while the power bank controls the temperature of the vest by powering interior heat panels at the chest and back. Three temperature settings controlled at the touch of a button: Blue = Low (38°C), White = Medium (45°C) and Red = High (55°C). This kit includes a 6,000 mAh Power Bank and will last up to 7.5 hours. A power bank with a minimum of 5,000 mAh is required to heat the vest.