A ball head is a metal or plastic apparatus placed on top of a tripod that increases stability and provides faster, more accurate rotation of the camera for the photographer. Ball heads allow the camera to be positioned in almost any direction with the aid of only one nut. They are lighter than traditional three-way pan-tilt tripod heads. With fewer parts and a much simpler mechanism, ball heads are usually preferred by more advanced photographers.
The disadvantage of a ball head is that it is much harder to work with fine positioning since all directions must be controlled at once.