The Macintosh Mouse used a rubber roller ball and a single, rectangle-shaped button. The first version of the Macintosh Mouse was beige to match the color of the original Macintosh, but was offered in platinum beginning in 1987 to match other Apple computers of the time.
This Macintosh Mouse design was based upon the mouse that shipped with the Lisa. The Lisa mouse also used the DE-9 connector and had a single button. The Lisa mouse used a steel ball for tracking.
Source: Wikipedia.com
