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

https://bizzmarkblog.com/is-ultherapy-fda-cleared-for-lifting-or-just-tightening/

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