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

https://juliusssmartcolumn.wordcanopy.com/posts/can-i-do-ultherapy-and-rf-together-or-is-that-too-much-heat

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