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

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, reaching deeper than most RF treatments, which heat skin between 40 to 45°C for collagen boosting. Compared to standard HIFU, Ultherapy offers more precise energy delivery