Keep Your Body ToastyBuilt in with quality carbon fiber heat elements for 9 core body parts, including your neck, back, abdomen, and waist, helping to maintain body warmth, promote blood circulation, and relieve pain as well as tension in muscles. USB-Powered for Lasting HeatUniquely powered by a portable charger with 2A or 2.4A USB output to keep warmth in and stand up against elements. Plugged into a 10000mAh battery pack (not included), this polished heated vest is capable of retaining warmth up to 7 hours at Low Level, 5 hours at Medium Level, and 3 hours at High Level. Lightweight DesignFeaturing quilted, lightweight design and fine interior lining for unrestricted comfort and coziness in fall and winter. With a zipper on the front, you can layer this unisex usb heated vest over varieties of tops to add a touch of style for refined looks. Package1* Heating jacket battery pack not included)