Heated Sole Therm-ic Insole Heat in anatomical 3D shape for optimal support. Stable support function for optimal pressure distribution in the shoe. The high-quality heating elements maintain the ideal temperature for the foot. Thanks to the cable located on the outside, the insole fits perfectly into any shoe. EVA foam structure. The Therm-ic C-Pack 1300 B battery is equipped with Bluetooth, allowing you to adjust the heating power remotely via your smartphone. The Therm-ic C-Pack batteries come with a USB charger, and a 220V charger is also available as an option. Up to 29 hours of warmth in your ski boots; equipped with a single control button; battery pack with USB charger; wall charger not included; package includes: 1 pair of Therm-ic Insole Heat 3D with cable, compatible batteries 1300B for up to 22 hours or 1700B for up to 29 hours, USB charger.