PLAY X STORE Optical Vertical Mouse,6-Button With DPI Switch,USB Mouse For Health And Comfort. Ergonomic vertical design:Using the most natural gesture to hold the mouse,avoid oppressing median nerve.It can help you ease or prevent pain on your hand while use for long time. Switchable DPI among 800-1200-1600-2400,sensitive and smooth optical tracking,meet your different demand of study,work or computer games. Back & Forward button are conveniently located on the left side of mouse,providing internet browser control with minimal hand movement. Unique thumb groove design,the angle and height are meticulous designed for health and the best comfort,fit your hand perfectly. Life of buttons and switch are up to million of times.USB port is compatibility,plug and play, also easy to operate.