Ultherapy uses ultrasound to target the 4.5 mm SMAS layer, making it popular...

https://www.cast-bookmarks.win/ultherapy-uses-focused-ultrasound-targeting-the-4-5-mm-smas-layer-to-lift-and

Ultherapy uses ultrasound to target the 4.5 mm SMAS layer, making it popular for lifting deep tissue without cutting. RF heats skin to around 40-45°C to boost collagen, great for mild tightening