Most mice come with a left button, a right button, and a scroll wheel. Not only does the mouse enable moving and selecting with the left mouse button, it can also be used to bring up alternative functions and menus by clicking the right button when hovering over a screen element. The mouse lets users zoom in and out quickly, and scroll up and down using the scroll wheel located between the two buttons. Advanced mice have extra buttons placed around the casing that can be assigned tasks and functions specific to the operating system or a particular program.