Ultherapy uses focused ultrasound to reach the 4.5 mm SMAS layer, which...

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

Ultherapy uses focused ultrasound to reach the 4.5 mm SMAS layer, which standard HIFU often can’t target as deeply. RF heats skin to 40-45°C for collagen boost but doesn’t reach the same depth