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

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

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