Ultherapy uses focused ultrasound targeting the 4.5 mm SMAS layer to tighten...

https://wiki-tonic.win/index.php/Ultherapy_Depth_Settings_%E2%80%93_What_Do_1.5_mm,_3.0_mm,_4.5_mm_Mean%3F

Ultherapy uses focused ultrasound targeting the 4.5 mm SMAS layer to tighten skin deeper than RF and standard HIFU, which mostly warm surface layers around 40 to 45°C