Must buy battery to warm About this item Worn Once- to big for husband... 100% polyester; Machine wash cold water on gentle or delicate cycle, line dry, no bleach, do not tumble dry, do not wring out, do not dry clean Made of lightweight Windshark 4-way stretch, waterproof, breathable windproof fabric Optimum placement of three heating panels keeps the upper body muscles warm and loose 7.4V rechargeable lithium-ion battery provides up to 10 hours of comfortable warmth Description Mobile Warming garments incorporate an integrated heated system that is powered by small lightweight lithium-ion batteries. Each garment features three heating panels lined with steel alloy fiber elements. The panels' heat reflecting properties and optimal placement on the chest and back provide quicker warm-up and excellent distribution of heat. Operation is easy; just connect the battery pack to the input cable found on the inside of the hand pocket. Simply hold the on/off button for about two seconds to activate. When the LED is lit, the garment will start heating up. Mobile Warming offers adjustable warmth and comfort settings for a relaxing fall day outside to a snowy winter's day on the mountain.