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

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, promoting gradual skin lift over 3 to 6 months. Compared to RF, which heats skin to 40-45°C mainly for surface tightening, Ultherapy reaches deeper for longer-lasting effects