Logitech's patented Optical Marble technology ensures smooth cursor movement, while 27 MHz cordless digital radio technology gives you reliable cordless freedom. The product offers advanced navigation features in a form-fitting, right-handed design. Its special drag-lock functions let you move text and images with ease, while Cruise Control scrolling lets you scroll rapidly through Web pages and documents by merely pressing a button. With conveniently located thumb-operated forward and back buttons, you can easily move through applications and Web pages without having to move the cursor to the browser's onscreen buttons. Two AA batteries (included) keep you powered for six months or more.