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

https://trulyexpatlifestyle.com/non-surgical-skin-tightening-in-singapore/

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