Mobile Warming Women's Jackii Vest Features The Windshark 4-way stretch high breathable, waterproof fabric provides additional flexibility needed in active outdoor sports Features three heating panels lined with steel alloy fiber elements Fabric features subtle embossed pattern Optimum placement with two panels on the chest and one on the back provide quick warm-up and even distribution of heat Includes one 7.4V 2.2Ah rechargeable lithium-ion battery and charger Battery features built-in 4-level thermo-regulating controls Provides up to 10 hours of comfortable warmth while enjoying favorite outdoor activities Reaches a max. surface temperature of 135F at full power Adjustable hem drawcord Specifications Mobilewarming Pro Heating System 7V 2.2Ah lithium-ion battery Current 1.0A Watts 15.0W Surface Temp 135F Battery Life 100 Power setting 135F 2.5 hours 75 Power setting 120F 3 hours 50 Power setting 105F 5 hours 25 Power setting 90F 10 hours