Safety and Effectiveness Evaluation of the High-intensity Focused Ultrasound Device for Lifting Lax Submental and Neck Tissue

Inclusion Criteria: 1. Male or female subjects aged 30 to 65 years, inclusive, at the time of informed consent. 2. Subjects presenting with mild to moderate submental and/or neck skin laxity, as determined by the investigator. 3. Subjects in good general health with stable body weight (±5%) for at least 6 months prior to screening. 4. Subjects willing to avoid other aesthetic or dermatologic procedures (surgical or non-surgical) to the treatment area during the study period. 5. Subjects able to understand and sign informed consent and comply with all study visits and procedures. 6. Female subjects of child-bearing potential who agree to use reliable contraception throughout study participation. Exclusion Criteria: 1. Prior facelift, neck lift, liposuction, or contouring surgery involving the lower face, submental, or neck areas. 2. Receipt of any energy-based aesthetic treatment (e.g., HIFU, radiofrequency, laser) or injectable aesthetic treatment (e.g., botulinum toxin, dermal filler, collagen stimulator) to the treatment area within 6 months prior to baseline. 3. Presence of any implanted electronic medical device, such as a pacemaker, defibrillator, or neurostimulator. 4. Active skin infection, wound, cystic acne, inflammation, or severe scarring within or near the treatment area. 5. History of keloid formation or abnormal wound healing. 6. Known bleeding disorder, or use of anticoagulant or antiplatelet medications that cannot be safely discontinued for the procedure. 7. Pregnant or breastfeeding women. 8. Subjects with a known sensitivity or contraindication to ultrasound-based procedures. 9. Any medical or psychiatric condition that, in the investigator's judgment, could interfere with study participation, safety, or data integrity. 10. Participation in another investigational study within 30 days prior to screening.