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

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

Ultherapy uses focused ultrasound to target the 4.5 mm SMAS layer, reaching deeper than standard HIFU, which works around 1.5 mm. RF heats skin to 40-45°C to stimulate collagen more superficially