The Deerhunter Heated Undershirt is powered by a rechargeable power bank with 3 heat settings for all day comfort no matter the weather. The integrated heat system includes two heating elements in the back where we mostly feel the chill. The heated undershirt has a zip neck, is soft to the touch and against the skin for added comfort and is machine washable too. With zip neck Integrated heat-system ON/OFF button 3 heat levels Two heat elements at back Machine-washable Pocket for powerbank Powerbank which is not included