Material: Nano gene heating fiberDesign: can be tailoredFunction: self-heating, warmth, moisture absorption and ventilationSuitable crowd: children, teenagers, adultsSuitable scenes: fishing, skiing, cycling, rock climbing, mountaineering and other activities 11. Self-heating principle: The nano-gene embedded in the insole can effectively absorb the energy in the environment and quickly convert it into heat and far-infrared, which is conducted and penetrated by the surface and the inside to produce a warming effect and also produce with the tissue cells of the foot. Resonance and resonance promote cell activity, thereby alleviating fatigue and accelerating metabolism. At the same time, it can effectively decompose microorganisms in the feet to create a healthy foot environment. 22. Warmth and comfort: The temperature rises to above 10, physical heating, continuous warmth, whether in cold winter or rainy day, the insole can provide wonderful comfort and warmth for your feet. Relieve the pressure and discomfort of shoes. 33. Anti-slip and breathable: It will not turn over or move in your boots or slippers. It can absorb the moisture produced by the feet and neutralize odors. Moisture-absorbing and heating fiber can be washed and cut. 44. Durability and support: The thick and fluffy high-density felt makes the insole remain flat like pancakes even after many times of use. The inner insole is the best cushion to prevent injuries due to improper foot support. They are perfect for all your boots, wide lace-up shoes, sneakers, tennis shoes and golf shoes. 55. Package content: 1 pair of self-heating insoles. The self-heating insole, which can be tailored at will, is an ideal Christmas and birthday gift for yourself, family and friends in cold weather.