Ultherapy uses focused ultrasound to target the 4.5 mm SMAS layer, helping lift...

https://technivorz.com/why-is-imaging-such-a-big-deal-in-ultrasound-skin-tightening/

Ultherapy uses focused ultrasound to target the 4.5 mm SMAS layer, helping lift and tighten deeper tissues. In contrast, RF heats skin to about 40-45°C mainly affecting surface collagen