After years of criticism for its one-button mouse designs, Apple responded in July 2000 by releasing a “no-button” mouse, the Pro Mouse. To be sure, one could still physically click the Pro Mouse, but the entire top of the mouse cantilevered downward as part of the action. The Pro Mouse also allowed the user to adjust the tension of the clicking mechanism to one of three settings by rotating a plastic wheel on the bottom of the mouse.
The Pro Mouse, which originally shipped in black, was Apple’s first mouse with an optical sensor in place of a ball. A 2002 update changed its color to white to match the iMac G4. In 2003, Apple simplified the white Pro Mouse, removing the tension mechanism and renaming it simply Apple Mouse.