This study will evaluate the clinical efficacy and safety of the BTL-899 device for changes in subcutaneous fat tissue and muscle tissue of arms. The study is a prospective multi-center open-label single-arm study. The subjects will be enrolled and assigned into a single study group. Subjects will be required to complete four (4) treatment visits and two follow-up visits. All of the study subjects will receive the treatment with the subject device.

This study will evaluate the clinical efficacy and safety of the BTL-899 device for changes in subcutaneous fat tissue and muscle tissue of arms. The study is a prospective multi-center open-label single-arm study. The subjects will be enrolled and assigned into a single study group. Subjects will be required to complete four (4) treatment visits and two follow-up visits. All of the study subjects will receive the treatment with the subject device.

At the baseline visit, MRI imaging will be performed; the subject's weight and arm circumference will be recorded. Photos of the treated area will be taken.

The treatment administration phase will consist of four (4) treatments, delivered 5-10 days apart. The applicator of BTL-899 will be applied over the treatment area. The device will induce visible muscle contractions along with heating of the subcutaneous fat. Each therapy session will last 30 minutes.

At the last therapy visit, the subject's weight and arm circumference will be recorded, and photos of the treated area will be taken. In addition, subjects will receive a Subject Satisfaction Questionnaire to fill in.

Safety measures will include documentation of adverse events (AE), including the subject's experience of pain or discomfort after each procedure. Following each treatment administration and at all of the follow-up visits, subjects will be checked for immediate post-procedure adverse event assessment.

During the post-procedure visits (at 1-month and 3-month follow-up visits), the subjects will undergo a MRI imaging. Also, the subject's satisfaction will be noted, and weight with arm circumference will be recorded. Photographs of the treated area will be taken. In addition, subjects will receive a Lifestyle Change Questionnaire to fill in.

Inclusion Criteria:

• Arm fat layer > 1.0 cm
• Age > 21 years
• Voluntarily signed an informed consent form
• BMI ≤ 35 kg/m2
• Women of child-bearing potential are required to use birth control measures during the
• whole duration of the study
• Subjects willing and able to abstain from partaking in any treatments other than the study procedure to promote body contouring during study participation
• Subjects willing and able to maintain her regular (pre-procedure) diet and exercise regimen without affecting significant change in either direction during study participation

Exclusion Criteria:

• Electronic implants (such as cardiac pacemakers, defibrillators, and neurostimulators)
• Metal implants
• Drug pumps
• Malignant tumor
• Pulmonary insufficiency
• Injured or otherwise impaired muscles
• Cardiovascular diseases
• Disturbance of temperature or pain perception
• Hemorrhagic conditions
• Septic conditions and empyema
• Acute inflammations
• Systemic or local infection such as osteomyelitis and tuberculosis
• Contagious skin disease
• Elevated body temperature
• Pregnancy, postpartum period, nursing, and menstruation
• Intrauterine device (IUD)
• Swollen or neoplastic tissues, space-occupying lesions or skin eruptions in the treatment area
• Basedow's disease