Etekcity Scroll M910 Wireless Vertical Mouse (60 Degree): 9 Clickable Function Buttons (Certified Refurbished) This Certified Refurbished product is tested & certified by Etekcity to look and work like-new. The product includes all original accessories, and is backed by a 90-day warranty Ergonomic vertical design(60 Degree) for optimal working comfort and and reduced wrist and arm strain 9 Function Buttons & 4 Grade DPI Shift: Up to 2400 DPI for maximum multifunction for games 2.4G wireless technology eliminates the hassle of short and tangled cords for limitless movement and control Thumb rest with rubber grip keeps your hand it an optimal position for comfort without slipped grip.Compatible with Windows XP/Vista/7/8/10(Mac can be used as a normal mouse except "internet""Forward" and "Backward" buttons)