Far-infrared rays have three characteristics: radiation/strong penetration/absorption and resonance (resonance). Far-infrared ray experts believe that far-infrared particles made of graphite minerals such as alumina, zirconia, titanium dioxide, and yttrium oxide give kinetic energy when electrified. , the excited far-infrared energy is the strongest, and the far-infrared rays with a wavelength of 9.35 microns can be used in rehabilitation medicine and preventive health care. Far-infrared rays are recognized as having a "thermal effect", which converts external electromagnetic waves into heat energy in the human body through molecular collision or radiation. Far-infrared rays have longer wavelengths and lower energy, so there is no risk of burns when used. Near-infrared rays and other electromagnetic waves such as ultraviolet rays and gamma rays will dissociate electrons on atoms, while far-infrared rays will not. Far-infrared rays are different from low-frequency (60 Hz) electromagnetic waves released by home appliances. Low-frequency electromagnetic waves released by home appliances will not generate electron ionization, but low-frequency electromagnetic waves penetrate walls and change human body currents. Physicians suspect that they are carcinogenic. Far-infrared rays are different. Since the human body emits far-infrared rays with a wavelength of about 9 microns, the penetration of external far-infrared rays to the skin is only 0.01 to 0.1 cm, so it is different from low-frequency (60 Hz) electromagnetic waves. Recently, in Japan, China and Taiwan, far-infrared rays have been used in adjuvant treatment of diseases, such as musculoskeletal aches, bed sores, and wounds that are difficult to heal. Far-infrared rays can be used to promote blood circulation and achieve the purpose of adjuvant therapy.