1. The ergonomic scientific design encourages a y neutral 'handshake' of the position of the wrist and arm, which makes the movement smoother and reduces overall fatigue. 2. 800 or 1200 or 2000 or 3200 DPI resolution optical tracking technology provides higher sensitivity than standard optical mice for smooth and precise tracking on a variety of surfaces. 3. Adding a forward or back button provides convenience for web browsing, a good option for Internet users, players and people who work long hours on a computer. 4. Our vertical optical mouse is compatible with Mac OS X, Linux and all versions of Windows computers. Due to its wired design, battery life is not a problem, and as a 'plug and play' device, connectivity to any desktop or laptop computer is achieved through the use of a simple USB port. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-YJL official store