Ultherapy uses focused ultrasound targeting the 4.5 mm layer beneath the skin...

https://golf-wiki.win/index.php/What_Should_I_Ask_a_Clinic_Before_Booking_Ultherapy_in_Singapore%3F

Ultherapy uses focused ultrasound targeting the 4.5 mm layer beneath the skin called SMAS, which few treatments reach. It triggers collagen buildup over 3 to 6 months for natural lift