[NATURAL HANDSHAKE POSITION] Wireless NEWTRAL Vertical mice has been designed in ergonomic natural handshake position and tested with criteria set out by leading ergonomists - promoting a more ergonomic posture, smoother movement, and lowering muscle strain [33° VERTICAL ANGLE FOR IMPROVED WRIST POSTURE] Unique 33° vertical angle reduces the pressure on your wrist, while your thumb is positioned comfortably on the thumb rest, reducing wrist pressure and hand fatigue by 31% [HIGH RESPONSIVENESS] With 2.4G wireless and 3 levels DPI to change among 800/1200/1600, NEWTRAL provides more sensitivity for smooth and precise tracking on a wide range of surfaces, things can be done quicker with a precision location sensor featuring a convenient click [HIGH COMPATIBILITY] Compatible with Windows 7/8/10/Mac OS/Linux systems. Instantly connect to your Mac Book / iMac , desktop, laptop, PC or other device by USB dongle.NOTE:Backward button invalid with OS system [CUSTOMER SERVICE] 3 years