HIFU (High - Intensity Focused Ultrasound) is a non-invasive (no traumatic) direct effects on the SMAS layer of ultrasound. HIFU's high-intensity focused ultrasound technology is an ultrasonic surgery technology that emerged in the 1940s. It takes ultrasonic wave as the energy source and uses its penetrability and focusability to focus the ultrasonic energy emitted by ultrasonic wave on the human SMAs layer, forming a focal region with high sound intensity within SMAs.It can penetrate subcutaneous 3.0mm-4.5mm to make the temperature of SMAs tissue reach above 65℃ in 0.5-1 second (the highest temperature of all non-invasive skin tightening instruments), which can cause collagen recombination in SMAs tissue without damaging normal tissue outside the focal area, so as to achieve the effect of fascia enhancement.