Ultherapy uses focused ultrasound targeting the 4.5 mm SMAS layer for a firm...

https://www.strobe-bookmarks.win/ultherapy-uses-focused-ultrasound-targeting-the-4-5-mm-smas-layer-for-a-deep

Ultherapy uses focused ultrasound targeting the 4.5 mm SMAS layer for a firm lift, with results peaking around 3 to 6 months