Ultherapy uses focused ultrasound to target the 4.5 mm SMAS layer deep under...

https://bizzmarkblog.com/is-ultherapy-fda-cleared-for-lifting-or-just-tightening/

Ultherapy uses focused ultrasound to target the 4.5 mm SMAS layer deep under the skin, encouraging natural lift over 3 to 6 months. Compared to RF, which heats tissue to 40-45°C mostly near the surface, Ultherapy reaches deeper for firmer support