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

https://wiki-aero.win/index.php/PDO_vs_PLLA_Threads:_What_Is_the_Difference_for_Lifting%3F

Ultherapy uses focused ultrasound targeting the 4.5 mm SMAS layer for deeper lifting, with results building up to 3 to 6 months. Compared to RF’s surface-level heating around 40 to 45°C, Ultherapy offers more precise depth