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

https://bizzmarkblog.com/is-ultherapy-fda-cleared-for-lifting-or-just-tightening/

Ultherapy uses focused ultrasound to target the 4.5 mm SMAS layer, stimulating collagen deep under the skin for gradual tightening. It’s known for visible improvements over 3 to 6 months