Our foot warmer strips contain iron powder, water and activated carbon. It can be extremely long lasting heating, safe and effective, by warming the feet, let the whole body warm up. The way to use it is very simple: first, clean your feet, then put on warm socks, tear them, stick them on the socks, your feet will slowly warm up, can last for 8 hours. After use, it can ensure that you are always warm when going out, so that you are no longer cold in winter and always warm.