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

https://technivorz.com/why-is-imaging-such-a-big-deal-in-ultrasound-skin-tightening/

Ultherapy uses focused ultrasound to target the 4.5 mm SMAS layer, a key support structure in your face, gradually lifting and tightening over 3 to 6 months