Ultherapy uses focused ultrasound to target the 4.5 mm SMAS layer, unlike RF...

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, unlike RF which heats tissue around 40 to 45°C without deep reach. Standard HIFU often doesn’t go as deep as Ultherapy or is less precise