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 compared to standard HIFU, which usually targets 1.5 to 3 mm skin layers. Radiofrequency heats tissue to around 40-45°C to boost collagen more superficially