Etekcity Scroll Endurance Vertical Gaming Mouse: Optical USB Wired, Adjustable DPI, 6 Buttons, Removable Palm Rest and Thumb Buttons (1 Year Warranty) Unique ergonomic design with removable palm rest to reduce hand and wrist pain and help prevent CTS Two thumb buttons for quick back/forward browser navigation and clickable scroll wheel Quick DPI shift button: 600 / 1000 / 1600DPI for seamless transition between users and applications High-resolution optical sensor with adjustable sensitivity for accuracy and responsiveness 1 Year Warranty by Etekcity; Compact size and excellent sensitivity, convenient to carry and easy to operate