"A journey of a thousand miles begins with a single step." Many western countries regard the foot as the second heart of the human body. According to the theory of biological holography, the foot has many reflection areas, which contain all the information about the health of human organs. Since ancient times, there has been a saying that "warm feet make the whole body warm". Through nerve reflex, the internal environment is regulated, stable and balanced. Mobilize the potential self-defense ability of human body and improve the immunity of the body, so as to achieve the effect of health care and physical fitness.
The interior consists of a raw material layer, a gelatin layer and a non-woven bag. The raw material layer is placed in a non-woven bag, and the gelatin layer is used to keep warm and stick to clothes. The raw material layer is a polymer composed of iron, stone, activated carbon, inorganic salt and water. Under the action of oxygen in the air, an exothermic reaction can be produced. But the key technology of portable warmth keeping is not reaction principle, but reaction control.