Nan Ya Polyester Warmth Retain Woven Fabric can keep body worm in the cold day.There are two item on the warmth retain fabric.One is used the hollow fiber and it contain dead air in the fiber.The dead air will cut off the cold air on the environment and the heat from body.The other one is fabric have nanoparticles in the fiber. The nanoparticles can absort light and transform it  to heat.The fabric can rise the temperature about 10 ℃ compare to the regular fabric.