Ultherapy uses focused ultrasound to target the 4.5 mm SMAS layer deep under...

https://fernandosgreatinsight.urbanvellum.com/posts/can-rf-tighten-skin-but-not-lift-what-does-that-mean

Ultherapy uses focused ultrasound to target the 4.5 mm SMAS layer deep under your skin, stimulating collagen over 3 to 6 months for natural lift and tightening