Ultherapy uses focused ultrasound targeting the 4.5 mm SMAS layer deep under...

https://hectorsmasterinsight.novacrestiq.com/posts/thread-lift-migration-how-common-is-it-and-what-does-it-look-like

Ultherapy uses focused ultrasound targeting the 4.5 mm SMAS layer deep under the skin, promoting gradual lifting and tightening with results peaking around 3 to 6 months