Constructed with durable deodorized polyurethane fabric, the Premium heated insoles provide all-day relief in cold weather conditions, whether it’s a frozen job site, a day in backcountry powder, an early morning jog, or late fall camping. With up to 7 hours of warmth from a single charge and seamless Bluetooth® connectivity powered by the proprietary MW Connect™ app, which you can easily download on the App Store® or Google Play Store®. The ultra-thin design fits in a variety of footwear, from work boots to running shoes or ski and snowboard boots and the integrated 3.7 V rechargeable lithium-ion battery recharges quickly.