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

https://extra-wiki.win/index.php/Is_Ultherapy_Really_Different_from_HIFU_in_Singapore%3F

Ultherapy uses focused ultrasound targeting the 4.5 mm SMAS layer for deep skin tightening, with results peaking around 3 to 6 months. Compared to RF, which heats skin between 40 to 45°C for collagen boost, Ultherapy reaches deeper layers