Your fingertips rest in a shallow groove on the buttons. This patented innovation secures the mouse in your hands and makes moving it much more precise. The ergonomic shape supports your hand in a handshake position. Since 2002, users continue to report that Evoluent VerticalMouse provides superior comfort and even relieves their wrist pain. An extra wide lip along the bottom edge prevents the last finger from rubbing the desk. Smartly-placed thumb buttons are both within easy reach at the top and bottom of a contoured thumb rest. A speed button behind the wheel allows convenient adjustment without releasing your grip from the mouse. Up to four lights show pointer speeds from low to high. A laser sensor ensures reliable tracking on most surfaces. Configure the buttons to perform nearly any function you wish — such as Copy or Paste — with fewer clicks and mouse movements. Dramatically varies sensitivity per notch in response to the speed you roll the wheel, from slow-and-precise all the way to hyper speed for blazing through long pages. Quickly lower your screen’s brightness to help reduce eye strain by simply rolling the mouse wheel. Easily change the brightness of the screen as your ambient light level changes.