The primary disadvantage of a trackball is its large size in comparison to a mouse. Trackballs also cost more and have a narrower range of options than other input peripherals. A trackball consists of a ball resting inside a socket that has sensors to note the ball's movement.
The trackball does offer several advantages over a mouse. It needs less surface on a desk or table to function. Because it doesn't move, the user doesn't have to keep moving it to get the desired effect on the screen. Trackballs offer more precise control, and they require almost no cleaning. The user's wrist and arm also undergo less physical strain, as they only have to use the palm or thumb and fingers to control the ball. These advantages make it popular for gaming and other applications as the increased precision is necessary for maneuvers with exacting requirements for accuracy.
One similarity between the trackball and mouse is that both devices feature buttons that provide additional functionality. However, while a mouse is sometimes more sensitive to the surface on which it rests, trackballs can function on just about any surface, making it more flexible than many other input devices available for computers and gaming systems.