Ultherapy uses focused ultrasound targeting the 4.5 mm SMAS layer for a firmer...
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 firmer look, with results peaking around 3 to 6 months. Unlike RF, which heats skin to 40-45°C mostly for surface tightening, Ultherapy reaches deeper layers