Only RF can produce a heat sensation, while hifu does not. It has two gears, one is the RF gear, which represents the energy intensity. The stronger the RF gear, the more obvious the heat sensation will be; the other is the HIFU gear, which represents the depth of action (1.5mm, 3.0mm and 4.5mm). It is recommended to use the third gear for the face. If the stratum corneum is thin, it is recommended to use the second gear. Then it is recommended to use 1.5mm for the forehead and 3.0mm around the eyes. The cheek is generally 4.5mm. If the skin is relatively thin, you can try to use 3.0mm first, and then use 4.5mm after you get used to it.