[12 HOURS LONG LASTING HEATING]: The heated foot insoles can continuously heat you up for 12 hours, with an average temperature of 40C. The foot heating pad simply opens the package and is ready to use, no electricity or additional heating is required. If the heat decreases, expose the heated insoles to air and shake well. [Easy to use]: the heated insoles activate right out of the package and heat up a few minutes after contact with oxygen (activated by air). When using, simply insert the heated insole into the shoe with the smooth side down. It is comfortable and practical, allowing you to enjoy the heat quickly! [NATURAL INGREDIENTS]: Warm and heated insoles are made of natural and safe ingredients, safe, colorless and odorless. After use, it can be thrown away with normal garbage. Note: Do not come into direct contact with the skin and no need to shake or knead before use. [Essential for winter heat]: The heated insoles are perfect for a variety of outdoor and winter activities.