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

https://www.bookmarkpage.win/ultherapy-uses-focused-ultrasound-to-target-the-4-5-mm-smas-layer-promoting-2

Ultherapy uses focused ultrasound to target the 4.5 mm SMAS layer for a deep lift, with results peaking around 3 to 6 months. RF heats skin to 40-45°C for collagen boost but doesn’t reach as deep. Standard HIFU is quicker but less precise than Ultherapy