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

https://www.hometalk.com/member/254051008/alice1337254

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