A Phantom quadcopter carrying a film camera in flight. The Phantom is an example of a miniature UAV (unmanned aerial vehicle) or drone. It is radio-controlled and powered by an internal battery, which drives its four rotors. Unlike most helicopters, quadcopters use two sets of identical fixed pitched propellers, two of which rotate clockwise and two anti-clockwise. These use variations of rotation speed to control direction and degree of lift. UAVs are used for filming and photography, including for surveillance purposes in both military and civilian arenas.