... ray, ultraviolet radiation, visible light, Infrared ray, MMW (millimeter waves), microwave, radio wave.Medically infrared ray with length more than 2.5 micrometer called far infrared ray. The infrared ray ... “natural generator of negative ion”, so it has 3 good reputation: “environmental police”, “air vitamin”, “atmosphere longevity element”Far-infrared magnetic tourmaline lumbar back ...