Ultherapy uses focused ultrasound targeting the 4.5 mm SMAS layer for a...

https://cruzinnp079.tearosediner.net/does-ultherapy-hurt-and-what-affects-comfort

Ultherapy uses focused ultrasound targeting the 4.5 mm SMAS layer for a precise, deeper lift, with results peaking around 3 to 6 months. In contrast, RF heats skin to 40-45°C to boost collagen at shallower depths for gradual tightening