✔ WHY SPECIAL : Unique Design - REDUCE TENSION - Scientific ergonomic design encourages healthy neutral "handshake" wrist and arm positions for smoother movement and less overall strain. It does take some time to get used to using a mouse at a different angle. Once you get used to it, you will love it so much ! ✔ HIGH RESPONSIVENESS : 800 / 1200 / 1600 DPI Resolution Optical Tracking Technology provides more sensitivity than standard optical mice for smooth and precise tracking on a wide range of surfaces, Sensitive Mouse Click with Less Noise. please confirm the size before buying it ✔ ADVANCE FUNCTIONALITY : Added next / previous buttons provide convenience when web page browsing; The superior choice for internet surfers, gamers and people who work at the computer. NOTE: The vertical mouse can not fully compatible with Macbook, Mac os x operating system. The backward and forward browsing buttons will not work, and the scrolling is contrary to Mac. ( Because Apple company product only support its own system) ✔ WIDE COMPATIBILITY : Compatible with most system including Windows 7 / 8 / 10, XP, Vista and Linux. Fit for Notebook, PC, Laptop, Computer, and other device. Not fully compatible with Apple products ✔ WHAT YOU GET : One Jelly Comb Wireless Vertical Ergonomic Optical Mouse, one 2.4G USB receiver ( IN THE BOTTOM OF THE MOUSE, Plug & Play), as well as our Lifetime Warranty Service. Offering you a FULL REFUND or a brand NEW REPLACEMENT if you are not satisfied with it