Ultherapy uses focused ultrasound to target the 4.5 mm SMAS layer for a deeper...

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 for a deeper lift, unlike RF that heats skin at 40 to 45°C mainly for surface tightening. Standard HIFU varies in depth but often hits shallower layers