Magic Mouse

Magic Mouse

Suddenly, everything clicks. And swipes. And scrolls.Introducing Magic Mouse. The world’s first Multi-Touch mouse.Now included with every new iMac. And available on its own for just $69.
Laser-Tracking Engine
Magic Mouse uses powerful laser tracking that’s far more sensitive and responsive on more surfaces than traditional optical tracking. That means it tracks with precision on nearly every surface — whether it’s a table at your favorite cafe or the desk in your home office — without the need for a mousepad.

Source - http://www.apple.com/magicmouse/