The Volt Heated Thermal Half Zip (THZ) is an extremely versatile mid weight jacket. The Thermal Half Zip is powered by a 5 volt USB powerbank battery that can be found at most retail stores. These batteries can be used for heating up the THZ or charging your cell phone. The powerbank must be rated for a minimum 1 amp output to properly operate the heat system. This athletic but stylish pullover jacket can be worn as a mid layer or outer layer depending on the outside temperature and/or your desired core temperature. The THZ features a two zone heating system that targets the back of the neck through the collar and the upper back between your shoulder blades. The patented Zero Layer Heat System provides optimal heat transfer, helping the heat to penetrate deep in to your body's core for a superior warming experience. By using a 3 level external silicone switch the user will be able to easily change heat settings and visually confirm which setting the jacket is on. As with all of the Voltheat.com products, the lower the heat setting you are on, the longer the battery will last. The Volt Heated Thermal Half Zip is made of a brushed fleece that helps your body stay warm and dry. The antimicrobial fabric will help keep the garment fresh and cut down on the frequency of washing. The Volt Heated Thermal Half Zip is machine washable once the lead wire is protected with the attached rubber cap. Features: 88% Micro-Poly shell fabric, 12% spandex Jersey with brushed fleece lining Antimicrobial treated fabric Contrasting top stitching accents Tricot brushed fleece stand up collar Includes 5V VB560 rechargeable powerbank battery and charging cable Machine Washable Zero Layer Heat System provides unmatched heat output: High 2 hours, Med 4 hours, Low 6+ hours Battery dimensions/weight: 2.75" x 1.25" x .75", 2.5 ounces Volt Heat Women's THZ 5V Heated Thermal Half-Zip Pullover