Comfy and warm! The Women’s Thermal Half Zip from our friends at Volt Resistance will have you wishing for cold weather. It may look like a stylish, outdoorsy top, but hidden in the back of the neck and the upper back are ultra-thin panels that take advantage of the patented Zero Layer heating technology that Volt Resistance developed. This allows the small stainless steel fibers that are woven directly into the fabric to radiate warmth to those key areas. The small, 5 volt battery connects to the top and is housed in a zippered, side pocket with a built-in switch located outside the pocket so you can adjust the temperature to high, medium, or low without accessing the battery in the pocket. With a fully charged battery, you can expect heat output for 2 hours on high, 4 hours on medium, and 6 hours on low. Even with the wires and heating technology, you can still conveniently toss it in the machine to wash and dry. The feminine cut, small sleeve pocket and comfortable brushed fleece interior are features that add to this being an ideal base layer or stand alone top for active TrailblazerGirls. As they say, put a “charge” into the cold with the Volt Resistance Women’s Thermal Half Zip!