input devices 
Electronic devices used to transmit data and commands to a computer.
Mouse whose case contains a movable rubber ball underneath to direct the movements of the pointer on the screen.
Movable sphere that moves over a flat surface (usually a mouse pad) to make the pointer move on the screen.
Removable part that surrounds the ball and closes the mouse case.
Device that detects the ball’s movements and transmit them to the computer.
Flexible cable containing the conductors by which the mouse is attached to the computer.
Smooth antiskid surface over which the mouse moves.