Heated Workskin base layer shirt uses carbon fiber heating elements to create and distribute heat to the chest and back. Powered by REDLITHIUM USB (Universal Serial Bus) battery technology. Combines a double lined polyester body and fleece lined arms, the midweight base layer provides a versatile layering piece for total body warmth. Features Raglan sleeves and seamless shoulders which allow for improved range of motion and comfort while working. Includes a quick-heat function that reaches the selected temperature 3X faster and one-touch LED (light emitting diode) controller with 3 heat settings. REDLITHIUM USB battery pack provides up to 3 hours of run-time, and there are heating zones in the chest and upper back. Washer and dryer safe. Made of pilling resistant fabric to extend product life. Includes base layer shirt, REDLITHIUM battery, USB charger/controller, and heavy-duty cord & wall plug.