Ultherapy uses focused ultrasound targeting the 4.5 mm SMAS layer for a deeper...

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

Ultherapy uses focused ultrasound targeting the 4.5 mm SMAS layer for a deeper lift, with results peaking around 3 to 6 months. In comparison, RF heats tissues to 40-45°C, promoting collagen but with a gentler lift