Electromagnetic wave takes its wavelength as the medium, which vibrates with the wavelength of human body to conduct heat energy, while electric heater conducts heat energy through air medium by radiation. * * * Vibration transmission efficiency is extremely high (in short, heat permeates deeply), especially for medical treatment, which has special effects on the focus; Others, through radiation heat conduction, only conduct heat to the surface of the object, and do not have that kind of penetrating power, so the efficiency is extremely low, especially for medical treatment, which is of little significance.