[. . . ] [. . . ] The 4D-scrolling roller and hot keys provide fast browsing on the Internet and access to multimedia. Plus, the ergonomic design with most comfortable grip and is great for long hours usage. With Ergo 600 you become more productive and efficient immediately. ▼Features: Cordless Technology The high performance RF Digital Radio Technology eliminates any risk of blind spots. For fast access to multimedia Previous/Next song; Volume up/ down / Play & Pause Convenient Roller Button For fast browsing up/down, left/right as well as zooming in Microsoft Office and Internet Explorer Advanced high precision 1200 dpi optical sensor Ergonomic designed for best gripping (Design patent No. [. . . ] [. . . ]