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

https://highstylife.com/thermage-vs-10therma-are-they-both-monopolar-rf/

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