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

https://mega-wiki.win/index.php/What_Does_MFU-V_Stand_For_in_Ultherapy%3F

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