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

https://landensnewperspective.hexaforgey.com/posts/is-numbness-after-hifu-normal-or-a-red-flag

Ultherapy uses focused ultrasound targeting the 4.5 mm SMAS layer for a gradual lift, with results peaking around 3 to 6 months. Radiofrequency heats tissue to 40-45°C for collagen tightening but works more superficially