Ultherapy uses focused ultrasound to target the 4.5 mm SMAS layer for a deeper...
https://www.bookmarkidea.win/ultherapy-uses-focused-ultrasound-to-target-the-4-5mm-smas-layer-promoting
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