The SKG F3 Massage Gun has precise control for appropriate strength. The built-in power battery pack uses the right strength to reach the fascia layer, in order to massage your muscles without making them sore. Compact and portable, the massager gun is lighter than majority of the market. There are four different heads: Spherical (for massage relaxation of the larger muscle groups), flat (for shaping and fitness massage), bullet (for deep tissue intensive massage), and u-shaped (for smaller muscle groups).