Your fingertips rest in a shallow groove on the buttons. This patented innovation secures the mouse in your hands and makes its movement much more precise. The ergonomic shape supports your hand in a handshake position. Since 2002, users have repeatedly reported that the Evoluent VerticalMouse provides excellent comfort and even alleviates their wrist pain. An extra-wide lip along the bottom edge prevents the last finger from rubbing on the desk. Skillfully placed thumb buttons are easily accessible both above and below a contoured thumb rest. A speed button behind the wheel allows for convenient adjustments without taking your grip off the mouse. Up to four lights indicate pointer speeds from low to high. A laser sensor ensures reliable tracking on most surfaces. Configure the buttons so that nearly any desired function—such as copy or paste—can be performed with fewer clicks and mouse movements. The sensitivity per notch varies dramatically depending on the speed at which you roll the wheel—from slow and precise to hyper-speed for scrolling through long pages. Quickly reduce your screen brightness to lessen eye strain by simply turning the mouse wheel. Easily adjust the screen brightness as the ambient light changes.