The Mobile Warming Womens Sierra Heated Jacket is constructed with Windshark, a comfortable 4-way stretch material. Windshark is ready to take on the elements. Look to this highly breathable, light-weight jacket to provide a completely waterproof and wind-resistant experience. The Sierra Heated Jacket has integrated, concealed heating panels powered by sturdy yet light-weight 7.4 volt Far-Infrared Heating System. The 7.4 volt system has three heating elements, one on the back and two on the chest, that add heat to critical areas that keep your core warm. The Sierras 7.4 volt heating system can provide temperatures ranging from 135F on high to 98F on low. On high, expect up to 4 hours of heat on high, and on low, the Sierra can provide heat for up to 11 hours! The Sierra has two ways to adjust the temperature. First, the built-in touch control button. With a simple button push, you can select from four heat settings. Second, they've incorporated Bluetooth control with our MW Connect app. Through the MW Connect app, you can quickly toggle through all connected Mobile Warming devices and adjust individual heat levels to your liking. MW Connect allows you to get real-time updates on battery levels and update your garments when new firmware becomes available. The Sierra Heated jacket is ready for any weather, and if outdoor conditions get cold, look no further than the Sierra Heated Jacket.