Tell winter you're bringin' the heat
Wear it under your jacket and over a light shirt to maintain core body temperature through the coldest jobs. Includes rechargeable 3000mAh Li-ion battery pack with three temp settings that keep you warm up to 4 continuous hours or cycle on an off for all-day comfort. Can also use any 5V 2.1 Amp USB battery pack. 2.0 fits chests up to 50".