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

https://www.bookmarkmaster.win/ultherapy-uses-focused-ultrasound-targeting-the-4-5-mm-smas-layer-for-collagen

Ultherapy uses focused ultrasound targeting the 4.5mm SMAS layer for deeper skin tightening, with results developing over 3 to 6 months. Compared to RF which heats skin to around 40-45°C for collagen boost, Ultherapy works deeper but can feel more intense