Never have cold feet again with the Heat Kit + C Pack 1700 from Therm-Ic. With this Heat Kit, you can transform any type of insole into a heated one! The included self-adhesive textile lining, which covers the upper part of each insole, can be easily trimmed to the right size. You then stick it onto the regular insole of your shoe, ensuring cozy warm feet while enjoying winter sports, thanks to the electric heating elements. The foot warmers are powered by two batteries that can be clipped onto the outside of the shoe. There are three heat levels to choose from, providing warmth for up to 17 hours. You can control the different levels with a button on the batteries or conveniently via Bluetooth using the Therm-Ic app on your smartphone. For longer outings, larger and replacement battery packs can also be added. The cable is routed out of the shoe at the heel and connected to the battery. If the battery cannot be fixed to the shoe, it can also be easily secured with an elastic Velcro strap. The battery packs, each with a capacity of 3350 mAh, can be easily recharged via USB.