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

https://weekly-wiki.win/index.php/PDO_vs_PLLA_Threads:_What_Is_the_Difference_for_Lifting%3F_26446

Ultherapy uses focused ultrasound targeting the 4.5 mm SMAS layer for gradual lifting, with peak results in 3 to 6 months. Unlike RF, which heats skin to 40–45°C mainly for tightening, Ultherapy reaches deeper layers