Features:*High-Quality Material: This heating insole is made of high-quality material, which is wear-resistant and durable, not easy to break, and can be used for a long time.*Fast heating and long-lasting: Constants temperature heating, comfortable and breathable, average temperature 40, fast heating, long time, high temperature, keeping your feet warm in cold weather.*Easy to carry: This insole is individually packaged, small and lightweight, and easy to carry, such as when traveling.*Easy to use: This heating insole can be used as soon as it is opened. Please shake the insole after opening to let the iron powder inside evenly absorb some airs. It starts to heat up and then put it into the shoe. It is simple to operate.*Recommendations for use: Try not to do strenuous activities when using this heating insole, but the heat will weaken if you stay still. If you take a few steps to let the airscirculate, the temperature will rise.Notice:*Actual color may be slightly different from the image due to different light effect*Please allow 1-3cm deviation due to manual measurementDescription:Materials: iron powder, water, activated carbon, vermiculite, water-absorbent resin, saltSize: 36-39/40-43Average temperature: average 40