There are two main types of mice, mechanical and optical. The mechanical mouse, the most popular type of mouse, uses a round ball which touches the surface of the desk. As the mouse is moved, this round ball also moves. Two rollers inside the mouse case make contact with the rubber ball, and are rotated by its movements. These rollers have encoders on each end which translate the movements into electrical impulses which are sent to the computer and decoded into x and y movements.
Most mice also have two or three push buttons.
These buttons are pushed to make selections or move items on the computer screen. Under Windows95 and WindowsNT, the mouse can be configured for a number of settings. These allow the behavior of the mouse to be adjusted to suit the individual. For example, the mouse pointer and shape, its blinking rate, its speed can be changed. In addition, the mouse can be configured for left hand or right hand operation.