Ultherapy uses focused ultrasound targeting the 4.5mm SMAS layer, promoting...

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

Ultherapy uses focused ultrasound targeting the 4.5mm SMAS layer, promoting collagen over 3 to 6 months for natural lift and tightening. Compared to RF which heats skin to 40-45°C mainly in the surface layers, Ultherapy reaches deeper tissues