Designed-for-Web scrolling (Designed to improve your online experience, the wheel also helps perfect scrolling when you're using other applications, such as Microsoft Office or Adobe PDF). Unifying. 18-month battery life. Precision scroll wheel. Mouse on more surfaces with advanced tracking. Contoured shape, textured rubber grips. No. 1 world leader in mice. Windows - Mac - Linux. A Wheel for the Web: Designed for how you use the Web, our newest micro-precise scrolling makes reading your Facebook, shopping Amazon or scrolling through Google searches easier. Plus, tilting the wheel moves you backward or forward on the Web (Tilt wheel will not support backward/forward on Mac computers but will support Dashboard, Expose or Spaces [when you select in System Preferences]). A Feel-Good Crowd-Pleaser: Based on the best-selling shape in the world (Based on independent sales data [in US currency] for CA, US, AU, FR, DE, IT , from September 2008 through August 2010), it keeps your hand happy - even after long hours of use - thanks to its comfy, contoured shape and textured rubber grips for easy handling. 18 Months, One Battery: With up to 18 months of battery life, it virtually eliminates the hassle of changing batteries. Smart sleep mode and On/Off switch save power, while an indicator light eliminates surprises (battery life may vary based on user and computing conditions). Plug it. Forget it. Add to it. This mouse includes the Logitech Unifying receiver. The tiny wireless receiver stays in your laptop, so there's no need to unplug it when you move around. Plus, you can easily add a compatible wireless keyboard or number pad, or even another mouse - without the hassle of multiple USB receivers. So long, touchpad: Forget about tricky finger maneuvers - with your laptop touchpad - at home, at school and at work you'll enjoy precise clicking and pointing while navigating your favorite websites thanks to Logitech Advanced Optical Tracking. And you don't need a mouse pad either. What's in The Box: mouse, Logitech Unifying receiver; 1 AA battery (pre-installed); user documentation. 3-year limited hardware warranty. System requirements: Windows XP, Windows Vista, Windows 7, Mac OS X 10.5 or later; Linus kernel 2.6+. USB port. Made in China.