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

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 deep, natural lift, with results peaking around 3 to 6 months. RF heats skin between 40 to 45°C mainly for collagen tightening but less depth