Ultherapy uses ultrasound to target the 4.5 mm SMAS layer, stimulating collagen...

https://www.list-bookmarks.win/ultherapy-uses-focused-ultrasound-targeting-the-4-5mm-smas-layer-promoting

Ultherapy uses ultrasound to target the 4.5 mm SMAS layer, stimulating collagen deep under the skin. It’s known for precise depth control and visible results that develop over 3 to 6 months