A mouse with a rubber or plastic wheel located between the left and right buttons (the "scroll wheel"). Also known as a "wheel mouse," when you move the wheel back and forth, it scrolls the content of the active window.

Introduced in 1996, the scroll mouse is very useful for viewing long documents and Web pages, all of which have a vertical (portrait) orientation. In addition to the regular left and right buttons, for quick navigation, some mice have two extra buttons on the side that default to previous and next page. Such buttons can also be programmed for other functions.