Ultherapy uses focused ultrasound to target the 4.5 mm SMAS layer deep under...

https://www.foxtrot-bookmarks.win/ultherapy-uses-focused-ultrasound-to-target-the-4-5-mm-smas-layer-reaching

Ultherapy uses focused ultrasound to target the 4.5 mm SMAS layer deep under your skin, giving a firmer, lifted look that unfolds over 3 to 6 months. Compared to RF heating the surface skin at 40 to 45°C, Ultherapy reaches deeper layers